It's not clear whether that's because of the OS or because the processor is M rather than U, or a mix. I'd have to test more to determine that. e.g. trying different OS same machine.

A better test would be if it was the same operating system on each of the computers. 

I saw a difference between the laptop with i7 xxxxU-win10 and the  i5-xxxxM-Win7. 

One may suspect that it's the OS that makes the difference.. 


The laptop with Windows 10 with the U,  is better at limiting load on the CPU than the laptop with Windows 7 and the M.

CPU load on windows 7 remains at 100%.

This is a picture from the Windows 10 machine



The figure there which in that pic I put to 33%, controls both the % load on the  processor, and the frequency of the processor, as shown by resource monitor.  

It doesn't do anything putting the figure in power options lower than 30%.. 

If you put the figure at 20% in power options, then the figures in resource monitor float/hover around at about 30%

So for best result one could put the figure in power options at 30% of 28% , less than that won't have any greater effect and is treated at ¬30%.  33% would be higher than it needs to be if trying to get the lowest cpu load and freq.

In both Win7 and Win10, The default for power saver mode is processor-100% on both battery and power.. But, Win10 is better.  On Win 10 even if the processor is set to 100% max processor, which is the default written in even on power saver..then when the power cable is pulled out, putting the laptop to battery mode, then it acts as if the figure was 30% (which is as low as windows goes).  The machine running Win7 can't do more than drop power by half.

**It is possible that the differences observed are processor related or not all **