High CPU when Idle/Monitor Blank on X1 [ Edited ]

[lloydz]

I have a factory fresh X1 with Windows 7, and have the Power/Display options in Windows set to No Screen Saver, and turn off the display after 10 minutes whether plugged in or on battery.  Without fail, after about 20 minutes of being idle, my CPU shoots up to around 90 or higher%.  I can't tell what the offending process is because the second I move the mouse and the screen returns, the CPU drops back to 0-5%.  I can confirm that my CPU was high because of my Windows Sidebar gadget which shows the high utilization in graph form.  I can usually tell when the problem starts as my fan cranks up to cool the laptop.  Unfortunately, each time I move the mouse and the screen comes back, the problem vanishes.  Any ideas on what to look for?

[MarcXW]

I have the same issue on my X1, I have all the latest drivers and BIOS, and I know that it is not software related as it has done this to me on Windows 7, fresh installs of Windows 8 Developer Preview, and Consumer Preview. I haven't looked at the processor usage per se, but I can hear the fan accelerating and Core Temp sometimes indicates the temperature going as high as 80C and as soon as I move the mouse, it drops back down slowly to 45-50C. I usually only leave my laptop in idle when listening to music while doing other things, which is when these things have occured.

[lloydz]

I'm glad to see I'm not the only one with this problem.

[lloydz · Accepted solution]

OK - I know this is an old topic, but I finally figured out what was causing my CPU spikes.  It turns out the offending process was "mscorsvw.exe", which compiles .NET assemblies in the background while my computer is idle:  http://blogs.msdn.com/b/davidnotario/archive/2005/04/27/412838.aspx

Running the command "ngen.exe executequeueditems" cleared up the problem.