Timing Calculation Consistently: Windows Update/Background Process Woes

Last Friday  4 December 2015 I was presenting a session at the Modeloff Global Training Camp in London. The session was “How to make your Excel workbooks calculate faster”, and so it involved demonstrations of timing formula calculation. No problem I thought, I will use my Surface Pro 3, recently loaded with Windows 10, Excel 2016 and FastExcel V3.

Why do my calculations take twice as long as they did yesterday?

But doing my final practice run-through on Thursday the formulas were calculating more than twice as slowly as earlier in the week. And my Surface Pro 3 was getting very hot. And the battery was running down very fast.

Of course when the Surface Pro 3 gets too hot it starts throttling down the I7 processor, but that would not explain a factor of 2, or why it was getting hot in the first place.

So I started up Task Manager and clicked More Details:

Task2In this example you can see that the CPU is running at 79% with Windows Search and Carbonite Backup chewing up most of the processor time.

But on Thursday it was one of the Service Host processes. Expanding it showed one of the services was Windows Update, and stopping that service moved the cpu % down to a small percentage.

Of course I had to remember to switch it back on next day.


If you want to get more consistent calculation timings:

  • Don’t let your Surface Pro 3 get too hot!
  • Use Task Manager to see what processes and services are running and chewing up the processors.
  • Temporarily stop any processes and services that are making heavy use of the processors.



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