Process Lasso

Process Lasso

Process Lasso is a software that will improve system responsiveness and stability.

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4.4 27 votes
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Process Lasso is Windows process automation and optimization software. From tuning algorithms like ProBalance to user-created rules and persistent settings such as CPU affinities and priority classes, Process Lasso enables full control over running applications!

Our famous ProBalance algorithm maintains system responsiveness during high CPU loads. This proprietary algorithm dynamically adjusts the priorities of running programs to keep problematic background processes in check. With ProBalance, no longer will single, or multiple, processes be able to bring your system to a virtual stall. Process Lasso will let you keep interacting with your computer, even when it is under a heavy CPU load. Try our CPUEater Demo to experience ProBalance for yourself.

Process Lasso also allows users to automate and tweak how applications are run through a number of unique and helpful functions. These include persistent priority classes, persistent CPU affinities, disallowed processes, per-process power profiles, a process watchdog for advanced rules, process instance count limits, multiple instance balancing and much more! These features give you the ability to control how programs utilize your computer’s resources based on automatically applied settings. With Process Lasso, you can decide exactly how you want your processes to run.

Process Lasso is the ultimate Windows CPU affinity changer. The CPU affinity specifies the set of CPU cores an application is able to execute on. With Process Lasso, you can control this with a persistent setting that applies every time the application is run, or change it dynamically while the application is running once a threshold is met. The CPU affinity is commonly changed to limit CPU use or improve performance.

Many additional functions such as power plan automation, a system responsiveness metric and process activity logging are also available.

For minimal resource use, all algorithms and process rules are enforced by a stand-alone background service called the Process Governor. The GUI is entirely optional.


  • Persist CPU affinities, priorities and more
  • ProBalance priority optimization
  • Proprietary responsiveness metric
  • Rules to act on processes when thresholds exceeded
  • Limit process CPU use
  • Automate power plan switching
  • Disable Hyper-Threading/SMT per-process
  • Balance multiple instances
  • Limit instances of applications
  • Disallow processes from running
  • Keep processes running (auto-restart)
  • CPU affinity changer
  • Keep PC awake
  • Native C++ for maximum efficiency
  • Stand-alone background service applies rules

What's New:

Process Lasso 9.5 is now available! Among other things, this version introduces Regular Expressions into rule process matching, enabling the creation of more complex and precise rules. In this initial release, Regular Expressions are limited to the CPU Limiter, Instance Balancer, and Watchdog features, but will be expanded throughout the product in the future.

Most home users need not concern themselves with Regular Expressions, so don’t be overwhelmed. If there is no need to use them, simply ignore them.

Other changes to this version include GUI optimizations and a lot of general product refinement. See the revision history here.

The new documentation on process matching in Process Lasso rules can be found below. For questions or problems, contact us.

Process Matching

When matching rules to processes, a match phrase is given by the user, often called the ‘process match’ in Process Lasso. This can be a simple process name, a string with wildcards, or even a Regular Expression checked against multiple process attributes (e.g. user and command line).


Traditional process name matching uses a simple wildcard match, with ‘?’ indicating any single character and ‘*’ indicating a sequence of any character. It is case insensitive. The user name may be appended to the match string with a colon. Depending on the feature, after toggling on path or command line matching, those fields are also compared to the match phrase.

Regular Expressions

Process Lasso v9.5+ supports Regular Expression (RegEx) matching to multiple process attributes. This allows for the creation of complex rules that were not previously possible. For instance, a rule could act on Chrome.exe or Firefox.exe when user is Bob or Jeremy. Previously, this would require 4 different rules, and in the case of the Instance Balancer, combining them into a single group was not possible.

Features supporting RegEx:

  • CPU Limiter
  • Instance Balancer
  • Watchdog
  • ProBalance Exclusions
  • Support for RegEx will be come to other features in future versions of Process Lasso.

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