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Using Windows 8 RP, my computer is sustaining a 26.6% CPU usage while sitting at the desktop doing absolutely nothing. The other day it was over 50%.

The entire usage is due to a process called "System".

I would blame a faulty task manager, but the usage must be legitimate, as my CPU temperature rises substantially during these periods of use.

My CPU is a 3.6ghz quad core, so the cause cannot be an underpowered CPU.

After a fresh restart, the usage will drop back down to a normal 0-1%.

Does anyone have any idea what's going on?

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I have the same problem with no driver updates in site. Tried installing Window XP and 7 without success. The computer is stuck with an annoying OS on its HD. – Noctis Skytower Nov 15 '12 at 18:55
Background indexing of harddrive? – Thorbjørn Ravn Andersen Jun 17 '15 at 6:33
dude... this question is like 3 years old and windows 10 is out in a month.. ;) – bitwise Jun 17 '15 at 15:31
up vote 4 down vote accepted

I noticed the same weird behavior with one of my machines(only one of them). As an answer, I could tell you that Windows 8 is still on it's release preview version, and not it's final release, so bugs can still happening. Additionally, I realised that my machine had a different LAN, WAN and Card Reader adapters than the other ones(which were OK), so, probably it is happening due to the fact that all these devices don't have proprietary drivers yet, they are running with Windows 8 default ones. Just wait until Windows 8 release and install proper drivers then this problem will probably miss.

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