Windows 8.1 Preview has disk usage of 100%, and the fan is very noisy. It started one week ago, before that it wasn't so noisy and the laptop worked very well. I don't know the cause. I hope you can help me.
Here is a screenshot of the Task Manager – the disk usage varies from 20 to 40 MB/s.
Best Answer
A physical drive issue would not cause those types of disk access rates in the operating system. I would be most concerned that it thinks 30MB/s is 100% utilization.
Since the offending process is SYSTEM, it means it is a kernel mode driver that is accessing the disk and not a service, I would start with updating all the drivers. It may also be pagefile access, so check for non physical memory usage of other processes.
It may be the antimalware software performing reads through a kernel mode driver.