Thank you for your guide! I have the same problem with the process "System" keeping the CPU constantly at 10-20%. Actually I have a vaio with "stamina-speed" switch. When I select "stamina" the CPU is constantly at 10%. When I select "speed" the CPU is at 20%. I followed your instructions and I think the responsible threads are ACPI and HAL. I tried to find a new BIOS but it seems that I have the latest one. I installed all the windows updates but nothing changed (I have windows 8.1). I changed my power saving setting but nothing improved. Please can you have a look at my DPC_Interrupt.etl because I don't know what else to do and this problem is eating my battery!
Here is my DPC_Interrupt.etl:
Thank you so much