Win 10 high idle cpu after update

System is using 25% CPU and antimalware service executable is also appearing at the top of the list with about 12% cpu use. My idle does not go below 55% so is heating up my dual core E8400 to 65 degrees celcius. I am sure the other day it was idling at 1%.

Using Windows 10 build 14393.105 (1607) x64

Will check my 32 bit of same build tomorrow.

Any fixes?

Sounds like a routine malware scan which should have finished by now.

Btw, I have a CPU of equal 2008 vintage, a Core2 Quad Q9300. I've certainly had my money's worth out of it but I think it's finally starting to fail. Hopefully it holds out until Kaby Lake hits retail.

My other 32 bit desktop E2180 is doing the same, idling at 59%, it was 100% until I removed the beta of anti.ransomware by mbam, now both machines are idling at 59%.

If its a scan it's taking over 24 hours on both machines.

Task Manager will show you what's taking the CPU

System is taking the most then defender taking about 20% each, which could be a scan, but bearing in mind both machines have ssd and disk use is 0.1% on both machines I'm not sure its a malware scan.

Try adding C:\Program Files\Windows Defender\MsMpEng.exe (Windows Defender) to the excluded files list in Windows defender

In reply to a post by BatBoy:

Task Manager will show you what's taking the CPU

Resource Monitor provides better information. You can find out exactly what system process is chewing up your resources.

You can get CPU breakdown from Task Manager as well, surely? I use the Detail tab and have added CPU time and all the I/O figures to the displayed fields.

Then I sort it on the column I'm interested in at the time. Usually CPU or CPU time or one of the I/O ones. Occasionally Name if I want to watch a particular process.

The anonymous SVs wrapping many functions seem to have disappeared in Win 10, presumably bundled in for this purpose with whatever they are running.

Found the rogue program. It was the Prey Project for tracking stolen devices. I have forgot my password so cant remove the devices but as soon as I uninstalled prey from both machines, idle cpu is now a steady 0% when idle. Prey hooks into the system so something must have changed in that last update so making prey obsolete and using high cpu usage.

I didn't know that it had been improved so much.