Now the QA Check Settings include an option Maximum number of parallel tests which enables controlling the CPU resources.

The initial display value corresponds to the number of available CPU cores (*2 for hyperthreading if available).

Leave this setting, if there are no problems such as jerky movement of mouse cursor.

Then the reduction of parallel tests (CPU cores) of one or two (depending on used machine) should leave enough performance for working without problems.

However, be aware that a test itself can use multi-threading, so that using the half of cores does not automatically mean the use of half of the CPU. If also other CPU-intensive processes shall be started, then you have to consider theses, too.