ParkControl Free – Tweak CPU Core Parking w/o Reboots

Latest version:

ParkControl v1.1.8.3

New – Optional system tray notifications when any process makes a change to the active power plan, and what process that made the change. Click below to expand screenshot …

ParkControl giving notification of a power plan change

  • Bitsum Highest Performance Mode
  • Access Bitsum Dynamic Boost‘ to dynamically change your power plan when your PC is active, and lower it when it goes idle.
  • Use the new Active Power Plan change notifications, know when and who changed your active power plan!
  • Support Bitsum’s Continued Independent Innovation!
  • BEFORE YOU BUY – If you see an error when attempting to apply settings, such as “ERROR: You do not have sufficient permissions”, this means your hardware, OS, or some other condition prohibits ParkControl from operating on your PC. Purchasing a license will NOT resolve this error!

License Terms

Lifetime Updates – Unencumbered updates to all future versions of ParkControl Pro. It can also be transferred between PCs as you upgrade

Bitsum developed ParkControl because core parking settings are hidden in Windows, but can make such a large difference on performance, particularly when there are bursting CPU bound loads (the most common type). After we noticed this, Intel later took action, moving the core parking control form the OS to the hardware, thus validating our findings!

Bitsum is an original innovator behind this tweak. Granted, it’s not rocket science, but sometimes the obvious needs stated. Further, we provide full technical details and information on how to make these tweaks without our software. Unlike others, we don’t hide our technology in a ‘black box’. Your purchase helps support our ongoing innovation, and we thank you!

Why ParkControl? Because OS managed CPU core parking causes real performance deficiencies! Read More  … 

Some features NOT available here are ProBalance and any others that are found exclusively in Process Lasso! Try it now.


  • CPU Control. Ability to tweak, unhide, and control CPU core parking and frequency scaling without reboots!
  • Bitsum Highest Performance. Create a power plan that auto-optimizes your hardware for max performance far beyond the system default ‘High Performance’ power plan.
  • Bitsum Dynamic Boost*. Auto-switch power plans when your PC goes active or idle. Stay running in Bitsum Highest Performance Mode while using your PC.
  • Power Plan Change Notification – Shows you when your active power scheme changes and what process initiated the change.

*Only Available with a Pro License!

I have Process Lasso Pro, do I need ParkControl Pro?

No, you do not *need* it. Process Lasso Pro is designed to take care of all this for you, dynamically. It’s pretty awesome, and has many other features. However, for tweakers, ParkControl Pro offers additional capabilities and automation over the more limited core parking settings of Process Lasso:

  • Real-Time System Tray Icon to Show Parking Activity
  • Acive Power Plan Change Notifications (by any process)
  • Easier Access to Frequent Settings
  • An IdleSaver-type automation called Dynamic Boost. This unique feature is one NOT found in Process Lasso, but Lasso’s IdleSaver does not have a ‘While Active’ power plan designation.

About Bitsum Dynamic Boost and Bitsum Highest Performance Plan

When you turn this ON it will instantly put you in ‘Bitsum Highest Performance’ power plan. This disables core parking and frequency scaling, and is something we manage and maintain for our users.

The flip-side of this feature is that when you go Idle for X time, it will go to ‘Power Saver’ (by default). So, visit the Settings of this option in the context menu of the system tray icon for ParkControl and be sure the ‘idle’ power plan it switches you to is what you want, and that power plan is configured like you want. For instance, Power Saver will let your PC sleep, so if you don’t want that, then turn off Dynamic Boost a minute, switch to Power Saver power plan, then go your settings and disable sleep (applying to the active power plan, Power Saver), then re-enable Dynamic Boost and go from there.

Process Lasso - Real-Time CPU Optimization and Automation


Benchmark results and images courtesy of XTremeHardware.

Core Parking

Core Parking is a sleep state, C6, supported by most modern processors and Operating Systems.

Core Parking dynamically disables CPU cores in an effort to conserve power when idle. Disabled cores are re-enabled as the CPU load increases once again. This technology is very similar to frequency scaling, in that it seeks to throttle the CPU when idle.

The problem is that Window’s default power profiles are configured far too aggressively when it comes to core parking, especially on workstations. Their interest was in conserving energy, even if this meant marginally decreasing performance. A number of complex parameters control when a core should be parked, and Microsoft tuned heavily towards power savings.

BTW, to deal with this issue, Intel changed Skylake to manage it’s own CPU core parking. Read more here…

The core parking settings in Windows are implemented as parameters of power plans (aka power profiles). That means you can, for example, disable core parking for the High Performance power plan, but leave it enabled for other plans. And that is exactly the desired tweak for most users: disable parking only for high performance power plans.


Empirical evidence shows that disabling core parking can make a real difference in system performance. There are many factors that will determine how efficacious it will be for any given system, including the CPU type, application load, and user behavior. However, we find that Windows is often over-aggressive in its core parking, resulting in excess latency as cores are unparked to accommodate bursting loads (the most common type of CPU load).

In our tests, we’ve found AMD processors benefit most from disabling core parking. This is perhaps due to the dramatic difference in the way AMD processors share (hardware) computational resources between logical cores. Microsoft optimized for Intel’s Hyper-Threading, which has much less capable secondary cores. AMD’s secondary logical cores are near full CPUs.

YMMV, but if we didn’t see real and substantial performance gains after disabling core parking, we wouldn’t have authored this utility.


These tweaks are entirely safe for any PC that is constructed properly. The only way that they could possibly seem to cause some change in behavior is if the PC has overheating issues. In such an event, those issues would be seen regardless of these tweaks by simply placing a sustained high load on the CPU.

Restore Defaults

  1. Click ‘Power Options’ in the ParkControl app
  2. Select the Power Profile you modified
  3. Click ‘Restore default settings for this plan’
  4. Repeat for all modified power plans

Changing Parking Settings Using ParkControl

Simply run ParkControl, select the target power profile, change the setting, and click apply!

What is that NUMBER that is shown on the GUI? That is the % of cores that must remain unparked. So, if it’s 25%, then 75% of the CPU’s cores can be parked at once (3 of 4).

Changing Parking Settings Using PowerCfg.exe

Here at Bitsum, we won’t force you to use our software. We’ll tell you how to do it yourself, the right way, unlike many other web sites.

Getting to business, you can change these settings yourself via Window’s Powercfg.exe. You must run this utility with elevated rights, so be sure to open an elevated console window by right-clicking ‘cmd.exe’ and selecting ‘Run as Administrator’ (now in the ‘More’ submenu in the latest Windows 10 update).

Also note that these commands adjust the current power profile. I felt it simplest to use these variables as opposed to giving you GUIDs that may or may not apply to your PC’s power profile setup.

FIRST, Backup ALL your Power Settings by creating a dump of everything to a TXT file. You can later use this to revert to your default settings.

powercfg /qh > powerconfig.txt

To mandate 50% of available cores always remain unparked, run:

powercfg -setacvalueindex scheme_current sub_processor 0cc5b647-c1df-4637-891a-dec35c318583 50

To adjust it so that only 25% of available cores remain active at all times, allowing 75% of available cores to be parked, you’d run:

powercfg -setacvalueindex scheme_current sub_processor 0cc5b647-c1df-4637-891a-dec35c318583 25

Yes, you can use ‘0’ – Windows is not stupid enough to park all cores at once, it will always leave at least one core active. In fact, this is usually the default setting when it is enabled. For example, to enable maximum use of CPU Parking for the power profile you are currently using:

powercfg -setacvalueindex scheme_current sub_processor 0cc5b647-c1df-4637-891a-dec35c318583 0

To disable CPU Parking completely for the power profile you are currently using, you’d want to run:

powercfg -setacvalueindex scheme_current sub_processor 0cc5b647-c1df-4637-891a-dec35c318583 100

APPLY New Settings, NOW!

After changing the power scheme settings for CPU Parking as desired, you then want to make the changes active by running the command:

powercfg -setactive scheme_current

When I first wrote this I included allowing specification of AC or DC (battery) values for the power scheme. Setting the DC power value isn’t documented, so I am going to skip that. Still, to do so you’d simply replace ‘-setacvalueindex’ with ‘-setdcvalueindex’. It also is not entirely clear if this is supported for every power scheme, though it certainly appears to be. Sadly, Microsoft’s documentation is quite scarce.

You should not have to reboot for these changes to take effect. They are immediate! Go ahead and check the Resource Monitor and verify that CPU Parking is indeed as you set it.

I hope this helps some people. Why would you go around making manual edits to the registry when powercfg can do the job for you? You shouldn’t. Registry edits are prone to mistakes and are generally more tedious and less clear.

How to Unhide Core Parking Options in Advanced Power Options

This gets tricky because not all settings apply to all models. There is, however, a general ON/OFF switch that DOES apply to all CPU models. Below we’ll present the most commonly used simple ON/OFF core parking switch, and how to show it in the Windows Advanced Power Options without any registry edits!


Execute the following commands to hide or un-hide the primary ON/OFF switch for core parking in the power plans.

Hide Core Parking Settings without direct registry edits (real-time, no reboot required!):

powercfg -attributes SUB_PROCESSOR cc5b647-c1df-4637-891a-dec35c318583 -ATTRIB_HIDE

Re-hide Core Parking Settings without direct registry edits (real-time, no reboot required!):

powercfg -attributes SUB_PROCESSOR cc5b647-c1df-4637-891a-dec35c318583 +ATTRIB_HIDE

How do I know if I have a Skylake processor?

If your CPU model is Intel Core i3/i5/i7 6xxx or certain Xeons, then it is. Otherwise, it is not. Unless you bought your PC recently, it is not.

Core Parking and Skylake

Due to the inefficiencies of OS managed core parking, Intel took over core parking in it’s latest generation of CPUs, nick-named Skylake. These thus have different core parking settings. The most important may simply be the ON/OFF switch of it’s Autonomous Mode, though there is also an aggressiveness %.

Autonomous Mode turns on/off the CPU’s ‘smart parking’, but does NOT turn off OS managed core parking. To do that, use ParkControl or the usual ways.

Unhide Skylake Core Parking Settings without direct registry edits (real-time, no reboot required!):

powercfg -attributes SUB_PROCESSOR 8baa4a8a-14c6-4451-8e8b-14bdbd197537 -ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 36687f9e-e3a5-4dbf-b1dc-15eb381c6863 -ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 4e4450b3-6179-4e91-b8f1-5bb9938f81a1 -ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR cfeda3d0-7697-4566-a922-a9086cd49dfa -ATTRIB_HIDE

Re-hide Skylake Core Parking Settings without direct registry edits (real-time, no reboot required!):

powercfg -attributes SUB_PROCESSOR 8baa4a8a-14c6-4451-8e8b-14bdbd197537 +ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 36687f9e-e3a5-4dbf-b1dc-15eb381c6863 +ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 4e4450b3-6179-4e91-b8f1-5bb9938f81a1 +ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR cfeda3d0-7697-4566-a922-a9086cd49dfa +ATTRIB_HIDE

Importantly, Skylake adds an ‘Autonomous’ mode that you turn on or off to disable core parking. Within this is a percentage to adjust it’s aggressiveness.

Windows Power Profile CPU Options for Skylake

Windows Power Profile CPU Options for Skylake

8baa4a8a-14c6-4451-8e8b-14bdbd197537 – Processor performance autonomous mode (Enable/Disable) Specify whether processors should autonomously determine their target performance state.

36687f9e-e3a5-4dbf-b1dc-15eb381c6863 – Processor energy performance preference policy (Percent) Specify how much processors should favor energy savings over performance when operating in autonomous mode.

cfeda3d0-7697-4566-a922-a9086cd49dfa – Processor autonomous activity window (Microseconds) Specify the time period over which to observe processor utilization when operating in autonomous mode.

4e4450b3-6179-4e91-b8f1-5bb9938f81a1 – Processor duty cycling Specify whether the processor may use duty cycling.

Click here for AnandTech’s excellent article on Skylake.

Click here for all pertinent power GUIDs at this time (Skylake and legacy).

No reboots required! ParkControl makes it’s adjustments in real-time.

There are also a few other sub-GUIDs that we have yet to fully research. To unhide them in the Advanced Power Options of Windows, use (remember, these may do nothing on your CPU model!):

Execute the following commands to hide or un-hide the primary ON/OFF switch for core parking in the OS:

Show Unresearched Advanced Options

powercfg -attributes SUB_PROCESSOR 06cadf0e-64ed-448a-8927-ce7bf90eb35d -ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 12a0ab44-fe28-4fa9-b3bd-4b64f44960a6 -ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 40fbefc7-2e9d-4d25-a185-0cfd8574bac6 -ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 4b92d758-5a24-4851-a470-815d78aee119 -ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 7b224883-b3cc-4d79-819f-8374152cbe7c -ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 943c8cb6-6f93-4227-ad87-e9a3feec08d1 -ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 619b7505-003b-4e82-b7a6-4dd29c300971 -ATTRIB_HIDE

Hide Unresearched Advanced Options

powercfg -attributes SUB_PROCESSOR 06cadf0e-64ed-448a-8927-ce7bf90eb35d +ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 12a0ab44-fe28-4fa9-b3bd-4b64f44960a6 +ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 40fbefc7-2e9d-4d25-a185-0cfd8574bac6 +ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 4b92d758-5a24-4851-a470-815d78aee119 +ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 7b224883-b3cc-4d79-819f-8374152cbe7c +ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 943c8cb6-6f93-4227-ad87-e9a3feec08d1 +ATTRIB_HIDE
powercfg -attributes SUB_PROCESSOR 619b7505-003b-4e82-b7a6-4dd29c300971 +ATTRIB_HIDE

Need More?

Get Real-Time Windows Optimization

Process Lasso ProBalance Technology improves PC responsiveness, eliminating micro-lags and. Process Lasso includes the Bitsum Highest Performance Power Plan that disables CPU Core Parking and Frequency Scaling for maximum bursting performance.

ParkControl Revision History

  • v1.2.6.8 – Fix issue where Bring-To-Front of an existing open main ParkControl dialog would cause persistence of TOPMOST style until you close the dialog.
  • v1.2.6.8 – Update Russian and Finnish.
  • v1.2.6.6 – Update to latest internal libraries.
  • v1.2.6.4 – Force application to terminate existing instances on relaunch to recover from any lost system tray icon and ensure that the main window always pops up.
  • v1.2.6.2 – Correct version resource block in last build
  • v1.2.6.2 – Fix two quick single clicks (not double) with right timing could cause a hang by causing 2 open windows. Synchronization objects fixed.
  • v1.2.6.0 – Fix missing system tray icon at startup for some users.
  • v1.2.6.0 – Improve product uninstaller (requires reinstall to get new uninstall.exe)
  • v1.2.5.8 – Fix ‘Kaby Lake’ labelled as Skylake and update to latest internal libraries (now all VS2015, no XP support).
  • v1.2.5.6 – Fix last build missing unicode languages
  • v1.2.5.4 – Switch to NSIS 3.01, many installer improvements
  • v1.2.5.4 – Improved check of compatible OS
  • v1.2.5.4 – Improved uninstall to use our new bcleaner.exe tool
  • v1.2.5.4 – Switch to NSIS inetc plugin for downloads, and back to HTTPS – no more failed internal installer downloads.
  • v1.2.5.4 – Reduce size of one-time (‘do not show again’) solicitation dialog
  • v1.2.5.4 – Latest language updates
  • v1.2.5.2 – Start adding new graphics set
  • v1.2.4.8 – Have updater re-check every time dialog is opened
  • v1.2.4.8 – Additional UI adjutments for non-standard displays
  • v1.2.4.8 – Update French
  • v1.2.4.8 – Misc code improvements
  • v1.2.4.6 – Re-apply unhide option on update to support any new power options that need unhidden
  • v1.2.4.6 – Control positioning adjustment to help people with non-default text sizes
  • v1.2.4.6 – Other UI adjustments
  • v1.2.4.6 – Remove web site page open on uninstall
  • v1.2.4.2 – Show auto-update message on main dialog if update detected at startup, so you don’t have to ‘catch’ the notification to auto-update
  • v1.2.4.0 – Fix issue with terminate on first start after update when co-intalled with Lasso v9 beta
  • v1.2.3.8 – Fix language auto-detect in last build
  • v1.2.3.6 – Add support for Microsoft Surface
  • v1.2.3.6 – Cosmetic improvements, especially for some languages
  • v1.2.3.6 – Attempt automatic language selection
  • v1.2.3.6 – Language updates
  • v1.2.2.0 – Fix language selection issue
  • v1.2.1.6 – Add system tray notifications for power plan changes, even by other processes (and able to name those processes).
  • v1.2.1.6 – Add Latency sensitivity hint processor performance GUID as an advanced setting we hide/unhide – not applicable to all CPUs or OSes.
  • v1.2.1.6 – Update Polish, German, French, Italian, and Russian languages.
  • v1.2.1.6 – First build to maintain beta branch (for next beta issue).
  • v1.1.8.2 – Add ability to re-hide settings
  • v1.1.8.2 – Shell out to powercfg to hide/show core parking settings
  • v1.1.8.2 – Fix installer bug when 32-bit OS user uses 64-bit installer
  • v1.1.8.2 – Add new sub-GUIDs
  • v1.1.7.8 – Re-open Settings each time Boost is enabled, so the user is more clear on options
  • v1.1.7.8 – Default to ‘Balanced’ for Idle power plan of Dynamic Boost
  • v1.1.7.8 – Minor fixes and maintenance
  • v1.1.7.8 – Update several languages
  • v1.1.6.6 – Fixes to ‘show core parking settings in Windows Power Options’ checkbox
  • v1.1.6.2 – Improved some post-update file system cleanup
  • v1.1.6.2 – Used latest language sets
  • v1.1.6.0 – Added option to show or hide these settings in Windows Power Options – for applicable CPUs
  • v1.1.6.0 – Added more precise CPU generation detection (for Skylake+)
  • v1.1.6.0 – Re-arranged dialog a bit and other minor changes
  • v1.1.6.0 – Fixed duplicitous language selection on new installs
  • v1.1.6.0 – Improved interoperability with Process Lasso (a little left to do for v9)
  • v1.1.3.2 – Add CPU type information to main dialog
  • v1.1.3.2 – Revert to prior power plan when Dynamic Boost disabled
  • v1.1.3.2 – Improve uninstall scenarios when using Dynamic Boost feature
  • v1.1.3.2 – Enable Dynamic Boost ‘Idle Power Plan’ selection.
  • v1.1.3.2 – Cosmetic improvement to Dynamic Boost settings dialog.
  • v1.1.2.0 – Fix issue in prior build where if BHP was not installed, ParkControl as a whole would not run.
  • v1.1.1.0 – Fix issue where Bitsum Dynamic Boost would decide to start using HP instead of BHP.
  • v1.1.1.0 – Fix some localization issues in dialogs and throughout. Update German.
  • v1.1.1.0 – Update German and Russian
  • v1.1.1.0 – Improvements to main dialog. Addition of ‘Bitsum Dynamic Boost’ checkbox and localization fixes.
  • v1.1.0.0 – Added ‘Bitsum Dynamic Boost’ feature to keep PC running in Bitsum Highest Performance, then drop to Power Saver on Idle for X seconds. It is Pro-only feature. Some work remains, but this lays down the base functionality (see system tray menu).
  • v1.1.0.0 – Improve CPU utilization and core parking graphs/bars. These may now function for a few when they did not in the past.
  • v1.1.0.0 – Fix expanding power plan combo boxes
  • v1.0.3.2 – Fix issue with secondary dialog instances having frozen CPU utilization graphs.
  • v1.0.3.2 – Update languages.
  • v1.0.3.0 – Add capacity to install or remove the Bitsum Highest Performance power plan to the GUI. On uninstall, it is removed if it was created only if Process Lasso is not also present (which also uses BHP).
  • v1.0.3.0 – Change code that selects default browser to use when opening hyperlinks.
  • v1.0.3.0 – Language updates.
  • v1.0.2.4 – Let auto-update work for everyone, licensed or not
  • v1.0.2.2 – Fix crash seen on right-click of icon in some cases
  • v1.0.2.2 – Optimize update check
  • v1.0.2.2 – Put Task Scheduler check in asynchronous thread
  • v1.0.2.2 – Add minidump support
  • v1.0.1.8 – Change error message regarding inability to set core parking changes
  • v1.0.1.6 – Improve updater
  • v1.0.1.6 – Fix race condition that could result in two main window instances under very rare timing
  • v1.0.1.6 – Update several languages, add Spanish
  • v1.0.1.4 – Fix to SHA2 binary signatures
  • v1.0.1.2 – Fix issue with CryptoPrevent security policy blocking ParkControl automatic updates due to temp folder execution prevention (will be noticed as fixed *next* update)
  • v1.0.1.2 – Fix Start At Login toggle would not stay off
  • v1.0.1.2 – Switch to dual-signing
  • v1.0.1.1 – Fix license info not visible in last update
  • v1.0.1.1 – Switch to dual-signed binaries
  • v1.0.1.1 – Updates several languages
  • v1.0.1.0 – Allow users with < 30 days installed (trial period) perform automated updates
  • v1.0.1.0 – Allow officially obtained ‘Free Trial’ license keys to perform automated updates
  • v1.0.1.0 – Added menu toggle ‘Start at user login’ to new Settings sub-menu
  • v1.0.1.0 – Added menu toggle ‘Check for updates’ to new Settings sub-menu
  • v1.0.1.0 – Added Settings sub-menu to system tray context menu
  • v1.0.1.0 – Minor fix to some Task Scheduler facilitating code
  • v1.0.0.4 – Update languages.
  • v1.0.0.4 – Latest Bitsum code base.
  • v1.0.0.2 – Fix issue where tray popup menu would continue to show after being clicked away from.
  • v1.0.0.2 – Minor optimizations.
  • v1.0.0.0 – First final release.


I have Process Lasso Pro, do I need ParkControl Pro?

I have Process Lasso Pro, do I need ParkControl Pro?

You do not need it, but you may prefer it. It adds to Process Lasso a system tray icon that dynamically changes as core parking does. It also has some automation that is similar, but not quite the same, as Process Lasso’s IdleSaver. Note that if both applications are installed, the menu item to manage core parking in Process Lasso will open the ParkControl app. Importantly, it can run without Process Lasso, which is it’s primary audience. Process Lasso Pro is the ‘big boy toy’ of this class.

In summary, ParkControl offers:

  • A real-time system tray icon to show core parking
  • Easier access to these settings
  • An IdleSaver-type automation with Bitsum Highest Performance Plan

I want to use Dynamic Boost, but my PC keeps going to sleep, and I don't want that. How do I fix this?

1. When your PC goes Idle, Dynamic Boost switches to ‘Power Saver
2. So, if you do not want your PC to sleep, you need to change that setting for the Power Saver power plan.
3. To do this, open ‘Power Options‘, find ‘Power Saver‘, and edit it. You can also switch to it, then change the sleep settings in their separate config area in Windows.

Will disabling CPU core parking and frequency scaling improve performance?

CPU core parking and frequency scaling can have a dramatic impact on real-time performance of bursting loads like audio/video, gaming, VOIP, and more. That is a big reason we have made such a ‘fuss’ over them. It was nice to be ‘vindicated’ by Intel, who has moved core parking control to the hardware in new CPU generations because the OS’s management was so sub-optimal. As long as they retain the ability to disable core parking, and I’m sure they will, it should be a good change. Microsoft seemed to focus entirely on battery life in recent years, leaving performance to suffer, particularly for desktop users.

Is ParkControl Pro included in Process Lasso? Can I run them together?

Yes, they can be run together just fine. They are designed to. Do you need ParkControl though? Well, you already have ‘Bitsum Highest Performance’ power plan, and it can be automated via ‘Gaming Mode’ and other mechanisms. You further have a non-system-tray ParkControl listed in the Tools menu of Process Lasso. The stand-alone distribution of ParkControl is for those who do not want to pay for, or use, a full-blown Process Lasso installation. The only other benefit to ParkControl is a system tray icon that dynamically changes when cores park, and perhaps easier access to quick core parking tweaks.

Should I manually edit the registry instead?

No, that’d be ridiculous. ParkControl makes these changes the correct way. The storage of the settings is backed in the registry, but why would you go hacking around in there when you can make these changes the right way and not risk damage? ParkControl’s changes to the system power plans are persistent, they don’t go away.

I get an error when I try to change settings. Why?

Are you a ‘Limited’ user? Is this PC on a corporate network? Have you done any ‘damage’ by doing manual registry edits? Are you sure your hardware supports core parking? In short, there are lots of variables. I recommend trying some of the powercfg.exe commands we list on this page in an administrative command console.

The core parking settings don't change after I hit Apply ...

That means your CPU or BIOS/UEFI does not support CPU core parking, or it has otherwise been disabled. Now, do also remember that this setting is specific to each power plan, so don’t get those confused and think your changes weren’t saved.

My CPU cores won't park! What is wrong?

First, if you never saw your CPU cores park, then it may be that your system just doesn’t support core parking. If you have seen your cores park in the past, but aren’t seeing parking activity, double check with the Task Manager or Resource Monitor (resmon.exe) to make sure it is not just a display error in the ParkControl GUI.

Do ParkControl's changes persist?

ParkControl changes settings of the Windows power plans based on your selections. These changes persist even if ParkControl is not running or uninstalled. For system defined power plans, you can reset to defaults in the Windows Power Options (linked to from the ParkControl GUI).

Process Lasso Pro

ProBalance In Action

Further Research

We’ve attempted to dig deeper into the core parking rabbit hole, and let me tell you there are countless additional hidden variables that control it’s behavior. It’s therefore not at all inconceivable that some are not tuned properly. In fact, Microsoft has issued Hotfixes in the past to address this very issue.

I’ll update my findings here as I’m able. If you want to support this project, buy a license for Process Lasso or donate.

Donate via PayPal or CC

  • Dan

    Hello, is there available the v. BETA 32bit?
    The installer available at: is still referred to the v.

  • I apologize, never noticed this comment. There is now a new beta series out, and certainly it is available in 32-bit form.

  • Dan

    Thank you very much indeed for your reply.
    I downloaded the latest 32bit version and now everything is OK.

  • I would like to note that any reader who likes ParkControl should definitely like CPUBalance. See

  • Stefano

    Hello, any support for Kaby Lake CPUs? Do they behave like Skylake ones?

  • Yes, it supports them just like it supports Skylake. However, since these CPU models control their own core parking, you are limited to ON or OFF basically – which is pretty much what everyone else uses anyway. There are also additional advanced power plan settings to help ‘guide’ your processor which ParkControl will unhide. There are several, so which applies to Skylake and which applies to Kaby Lake we are still sorting out, but I’m attempting to ensure only relevant options get unhidden (irrelevant options will do nothing).

  • Stefano

    Indeed, disabling core parking is what I need. I confirm it works fine with Windows 7 x64 (I managed to install it on a Kaby Lake computer, even if unsupported) and can really see the difference with audio applications. However I didn’t notice any difference using ParkControl on the same computer running Windows 10 x64 (dual boot). Weird..

  • It could be that the scheduler of Windows 10 is more aware of the type of processor than was Windows 7. Awareness of the characteristics of a processor can turn core parking from almost harmless to extremely detrimental. The devil is always in the details ;).

  • Stefano

    Yes, it could be. Interestingly my tweaked Win7 (also thanks to disabled core parking) achieves much better performance than Win10. The same audio project results in almost 10% less CPU usage on Win7! So far I’m really unimpressed by Win10 performance with real-time tasks. But that’s another story…

  • There’s a lot on top that interferes with real-time stuff. Win2016 Server is probably where you’ll end up again in the end – and it is great.

  • EKMA

    Question – I’m currently running a Phenom II X4 3.2Ghz processor with a 760gm-gs3 motherboard (I know…it’s crap, but, the new upgrades are on the way…lol).

    Anyway, I am running ParkControl and have noticed something that seems odd. The thing is that I set it up on Bitsum’s Highest Performance and played Battlefield 1 on 1600×900 (nvidia gtx 660ti). The game ran pretty well…it did have some frame rate drops from 60 to 24-25, but, would go back up in a second or two and stay steady for a while.

    Tonight, I turned Freq Scaling DC to “Enabled” at 5% and noticed two things: 1) that the visuals seemed to have more detail…glare from lights, fire embers looked more realistic, etc. and 2) that the frame rates never dropped enough to cause the glitchy, bouncy feel I would get previously. I searched to find out exactly what the different adjustable items exactly were, but, couldn’t really get a clear answer. On a side note, Parking AC, Parking DC, and Freq Scaling AC are all disabled at 100%. Is this strange? Or, am I just imaging a difference that really isn’t there? I get that the AC/DC are Alternating Current and Direct Current, but, why is there an adjustable AC and DC for the two different options? Hopefully my question makes sense…if not, disregard it and call me an idiot (which I obviously am…lol).

  • There is so much pseudo-random activity going on with PCs and your network that there are too many variables while playing games that quick subjective observations like this can be chalked up to coincidence. I would say what you have guessed: you had no frame drops and things ‘seemed more detailed’ (very subjective) due to happenstance. You would need to do much more testing to even draw a reliable *subjective* conclusion. If you had weeks of data or a reliable test bed, then I could analyze this paradoxical response, but for now I would not make anything of it and quit looking so hard for marginal performance gains and losses. These will happen pseudo-randomly no matter what you do (usually just when you don’t want them to ;p).

  • EKMA

    I’m gonna go with your analysis…*bows down and slowly walks away from the keyboard*

  • Madpaddy31

    I’m having a strange bug with PCNTRL, im using win 10 64.When using the dynamic boost after the PC has gone into idle/ power saving mode it wont switch back to high performance unless i do it manually.

  • I knew I saw this comment in passing somewhere…anyway, now that I have found it, this could be caused by a failure to have properly created the Bitsum Highest Performance power plan, or it was unintentionally recreated. Please try a remove/add of that power plan (via ParkControl), then restart ParkControl and see if it runs as intended. In the meantime, I will certainly check out safeties to be sure, as this should never be the resulting state. Thanks for the report!

  • I deleted my prior wild theory, which as I said, comes down to ambient room temperature *or* Idle load temperature, basically. It is just not plausible enough for me to be spouting about, I just think about these things because it is my job.

    I did add to the above comment network I/O as something that I neglected to mention as a major random factor in a lot of online gaming. I mean, a little latency may kill your FPS, as you well know.

  • LazyAdmin

    Hello, thank you for your excellent information on this webpage regarding CPU parking… I’m trying to use your App to determine why CPU cores are being parked on my newer Dell models (7040, 7470) with Skylake processors. It’s difficult for me to reproduce or get the system to park the cores, but when it happens, 3 of the 4 are parked and they do not seem to “un-park” unless I reboot or set processor performance parking min cores to 100%. After reboot the problem eventually returns.
    Any suggestions on how to determine what is causing this and the best approach to making sure it doesn’t occur in the first place? I’m less concerned with power consumption than performance for my users.

  • Thank you! Skylake CPUs manage their own core parking for increased efficiency. Thus, ParkControl is basically ON/OFF for any given power plan. However, you can unhide the settings in the Windows Power Options (the checkbox in ParkControl), then go visit the Advanced setting of the desired power plan(s). There are several new variables, but which are applicable we are still wading through, so from there you’d have to just explore. Skylake uses things like ‘hints’ the OS is about to become more active and more.

  • LazyAdmin

    Thank you for your prompt response. If I’m understanding you correctly, you haven’t determined exactly what options need to be tweaked in order to completely turn off core-parking with Skylake CPUs? I’m considering just changing the Minimum Processor state from 5% to 100% so it never throttles/parks… or is this something you would advise against? I’ve seen mixed opinions around the web. Thanks!

  • NO! That is NOT the conclusion I meant to convey. I meant to convey that with ParkControl core parking is ON or OFF with Skylake, individualized tweaking is up to you, and nobody publicly published a good map and description of most of these features yet. I have no idea what is up with your system, and you should consider a bug in ParkControl’s UI that causes it to ‘freeze’ in it’s display. I have that documented as a rare bug, so it could be all you are seeing is that! (note: this bug won’t exist long, if it is the case, but I feel it important to mention just in case).

    Note I am on a Skylake system now and it works fine, but TL;DR; validate what you see in ParkControl with the Windows Resource Monitor or Task Manager in case it is that rare bug. And be aware of the power plan you are in, always. Let me know!

    Finally got my reply right ;). As whether I would advise against it. Look, let Process Lasso(or ParkControl Dynamic Boost) manage this. When you need the performance, turn off parking by entering the Bitsum Highest Performance power plan. When you don’t, use the Balanced power plan. Keep in mind for mobile devices both AC and DC configurations exist for each power plan. Thanks!

  • LazyAdmin

    Sorry for the confusion.. I am/was really only using the ParkControl App to help determine what is causing my cores to become parked in the first place. The app DOES usually work to unpark them, but I need a solution I can deploy out to many computers and not have to rely on an app to react to the problem if/when it crops up. Basically I need to ensure it just doesn’t happen in the first place.
    So I guess my question really is, what is the recommended way to disable core parking on Skylake CPU aside from using the Parkcontrol App? Probably a question I need to ask of Intel.

  • ParkControl should toggle the ability of the cores to park themselves. It does in my tests anyway. I think there is an unrecognized factor in this case, and I do not know what it is. Remember that the parking settings are power plan specific, AC/DC specific, etc… but you know that. I just don’t know how to explain what you are reporting, and don’t see it myself :o. It *could* be some sort of forced parking due to high thermal load I suppose, but that is me grasping at straws,

  • HumpsA003283828

    Please update to Kaby Lake CPUs, I am currently running a Kaby Lake and your software shows it is a Skylake.

  • Already on the task list. You should see an update in the next couple days.

  • HumpsA003283828

    Wonderful, thanks for the quick response :)

  • Samehi

    Hello.. I have CPUBalance. is it ok to have CPUBalance & PerkControl running side by side?

  • Yes, perfectly fine!

  • HumpsA003283828

    Got the update ( and yup it no longer shows Skylake at the end, but just says “Intel64 Family 6 Model 158 Stepping 9, GenuineIntel”. I thought it should say Kaby Lake at the end, but if that was your intent then it’s fixed.

  • It will show it next build. I do what I can. I am working on more critical code in Process Lasso right now (could be vice-versa, but there is only one of me!).

  • HumpsA003283828

    understood :)
    all good

  • If you want, you can help me test, as I do not yet have a Kaby Lake in our ‘arsenal’ of test beds. Email if interested…

  • Larry Gall

    I have a strange problem, although it’s just a minor one. When I reboot, the power plan is always different, and seems to be random from what it was set to when I restarted. I watched this carefully and it does it nearly every time with different results. Sometimes “Bitsum Dynamic Boost” enabled, sometimes not, shut down with “power saver” and restart with “high performance. Something changed because it used to work normally.

  • That sounds odd. Are you also using Process Lasso? Any chance of conflicting rules that create a race condition? Otherwise, I am not sure, but will check over everything and be on the lookout.

  • Larry Gall

    Thanks, and I wouldn’t worry about it if I’m the only one mentioning it. I had a failed Creators Update in Win10 that also caused problems with Actual Multiple Monitors (since solved) as well, so I’ll re-image my machine to an earlier time and try again. Besides, it’s really no big deal to check the state when I boot up. Thanks for great software.
    – Paid / Registered user.

  • I have heard of a lot of people having trouble with this creators update (I mean with it, not with Lasso, or anything to do with ParkControl, or Bitsum). It did fail on my primary workstation, but my Surface took it.

  • Kimi R

    far better programs out there offering far more than this developer is, at no cost..

  • Ok, I’ll bite. First, ParkControl *is* free, even though Pro features are offered as an add-on (better than relying on ad revenue from fake download buttons that spread malware, imho). What are the ‘far better’ programs that offer this same function? And why are they far better, aside from being ‘freer, but lacking all Pro features, so really just as free’?

  • Note that I have not restricted his ability to post, he just has no answer. I am aware of the other utilities out there, and despite that we have been given no credit for being one of the very first to start educating consumers and provide freeware… Yes, ParkControl *is* FREE, except for the Pro features, which no other software has. So, you can be turned off, but we forever made a difference in this area, so you are welcome for that, even if you never appreciate it.

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