CpuHog is a utility to track Windows processes in order to uncover those that that use a lot of resources for a short period. This is useful to ensure the smooth running of Microsoft Flight Simulator which is sensitive to the fluctuations in CPU availability.

The CpuHog executable and runtime window


The ‘Now’ reading is the elapsed time vs CPU time for the past second. The actual elapsed time for each process is calculated individually so even if there is some jitter in the execution of the program, the result should still be reasonable accurate.


This value represents the average percentage of an active task. The Now result of activity is summed and counted to provide an average. Activity that doesn’t breach the 0.001 minimum is treated as zero and is ignored. In this way, intermittent processes collect an active average that is not affected by inactive periods. The averaging includes all active values throughout the life of the process.


The list of results are sorted into Max% order so you can find the most intrusive processes at the top of the list.

Colour Coding

  • Grey entries have an execution time less than 0.001.
  • Dark green entries are currently active with a Max% of less than 1 logical processor
  • Red entries are currently active with a Max% of more than 1 logical processor

‘Active’ Threshold

The program uses 3 decimal places to report values as a convenience to the presentation and internal logic but the actual accuracy of the app depends on timers and software outside of the apps control. To be safe you should assume the reported numbers are an approximation.

To separate active from inactive processes I have used 0.001 as an arbitrary minimum value because it can be shown simply onscreen and coincides with the use of 1ms as the primary unit of time.


The algorithm is comparing elapsed time to processed time and divided by the number of logical processors. This appears to be equivalent to the reports in the ‘Details’ tab of the Task Manager.

CpuHog's results vs the details tab of Task Manager
CpuHog’s results vs the details tab of Task Manager