Surface Pro 2 "System Interrupts" high CPU

The Surface Pro 2 is excellent hardware, but the software lets it down in various ways.

All told, it's still the best Windows machine I've ever owned, but it definitely needs a lot more work.

Here's a weird thing I hit today : I was losing around 15%-25% CPU on "System" and "System Interrupts".

I had installed c. 1.5GB of updates in the last several days - maybe that caused it?

Hmmm - there was one other thing I changed, this morning.  Maybe that caused it?

I changed it back - and the problem went away!

So : if your Surface Pro 2 runs fine after a reboot, but is wasting a lot of CPU (and hence slashing battery runtime to just an hour or two) with "System" and "System Interrupts" after putting the machine to sleep and then waking it up, there is a chance it might have something to do with this :

This morning, I went into Device Manager and disabled "Allow this device to wake the computer" in the "Power Management" tab in the Device Properties for each of the two "Mice and other pointing devices".  (I suspect one was the touchscreen and the other the Type Cover's trackpad, but they both simply showed as "HID-compliant mouse".)

I had already - weeks or months prior - done the same for the Keyboards, but that had seemed to have no effect at the time.

What I was trying to accomplish was have it that any accidental keypresses or mouse movements would not wake the device from sleep.  I wanted to know that only pressing the power button, or perhaps the Windows button, would wake it.

I at last had that behavior!  When I had only disabled wake-the-computer for the keyboards but not the mice, the keyboard would still wake the device.  I guess that because the Type Cover has both keyboard and mouse together, I must've needed to disable the wake-the-device option for both or else power would remain to both and both would remain able to wake the device.

So this morning I was very happy for a short while, because no action on the Type Cover would wake the device.  Just what I wanted!  But I quickly discovered serious side-effects.  nircmd no longer worked to turn the screen off.  And this "System" and "System Interrupts" high CPU usage bug!!!

I lost a few hours trying to get things working, and finally realized the "System" and "System Interrupts" high CPU usage might've been a strange side-effect from disabling the allow-to-wake-computer options for those two mice.  I reverted that setting, and voila - nircmd resumed working and the "System" and "System Interrupts" problem went away without even a reboot!

Don't ask me how to fix the problem in your case, and don't ask me why changing that particular setting would have such seemingly unrelated side-effects, but if you're desperately searching for clues, my case adds a few more.  I hope it helps someone!