I have just built my own PC (i7 5820k, GTX 970, 32GB memory) and quite often it suddenly becomes slow and unresponsive. I have ran checks on my HDD's and SSD and they say there is nothing wrong, also my GPU, CPU and memory never runs more than around 10%. Restarting the computer fixes the issue. How can I troubleshoot this problem? Below is a screenshot of my task manager whilst the PC is slow.