Low responsiveness is the most common reason why people think that their computer is slow. Usually they blame the operating system, and in particular Vista. However, assuming that the hardware is as modern as the operating system, the real culprit is usually an application that had gone mad. This doesn’t necessarily mean that the program has crashed and is in an endless loop that is consuming all of your processor power. Some applications just misbehave by pushing other programs aside, claiming most of the resources for themselves. Sometimes it can take several seconds for a program that has already been loaded to respond to a mouse click.

Process Lasso is the perfect name for a tool that brings a mad program to its senses. The program’s ProBalance feature constantly monitors all processes, and if an application’s claim for CPU resources exceeds a configurable threshold, Process Lasso will reduce the priority of that program’s process. As soon as the process’ CPU usage falls below a second threshold, Process Lasso will restore the original process priority.

To understand how Process Lasso works, you can use Cpukiller, the tool I blogged about yesterday, as a demonstration. Cpukiller runs at high priority and as a foreground process. Thus, you have to allow Process Lasso to manage foreground process, and processes with non-normal priority, and (see screenshot). If you then let Cpukiller consume 100% of your CPU’s resources, Process Lasso will automatically set Cpukiller’s CPU priority to “Below Normal.”

Even though Cpukiller is still running, your PC’s responsiveness will be normal. If you then reduce Cpukiller’s slow-down factor to below Process Lasso’s threshold, Cpukiller’s process priority will be automatically reset to “High.” You might also like to try running Cpukiller at a slow-down factor of 100%, without letting Process Lasso interfere. The responsiveness of your PC will then be close to 0.

Process Lasso has a couple of other features that can be helpful in improving the responsiveness of a computer. You can configure default process priorities, default CPU affinities, boost foreground processes, configure disallowed processes, limit the number of instances of a program and more.

Process Lasso is only free for private and academic use. The prices for the professional version start at $24.95 per seat.