I have a quad core laptop with win7. Around 3 months ago the laptop occasionally slowed down.
Resource Monitor and Process Explorer show that processor 0 was 100% busy with DCP and Interrupts. A restart temporarily has helped, but the problem returns.
(I rarely turn of the machine, I just close the lid and let it hibernate.)
At first I though this might be something with the IO, a disk fail or similar.
As another superuser question suggested I downloaded DPC Latency checker, and I indeed had a big latency. As suggested, I disabled drivers one by one, and found the problem: my Atheros ethernet card.
I tried downloading newer drivers, but they are up to date, so I just disabled it for good. I am using WiFi anyways. I opened up process explorer, and to my surprise, the processor was still at full use. So I had to take a different approach.
I have downloaded before the windows performance tools. After running
xperf -on Latency I have found that ACPI.sys was taking 15.77 % of duration compared to the rest which was lower than 0.1%. I tried disabling ACPI-Compilant-Control Method Battery but it has not helped. Is it safe to disable other devices such as management interface for ACPI? I have no idea what this might be.
EDIT: It seems that there is a high chance to trigger this when i plug the computer in power. As one post suggested, when i put the computer to sleep, the high usage goes away again.