Hello. I updated my Windows 10 today to the 1803 build, and it seems that drivers weren't fully installed since it says in the notifications center "finish installing drivers" with a red flag. I have an i7 4770 @3.5-3.9GHz, and the CPU usage is ranging from 50% to 100%, but I can only see 23-30% being used by the process Server Host: Local Service (network restricted) - Expanded it shows windows audio, 10% by Windows Explorer, and like 11% by Avast service. Stopping the windows audio service is the only thing I did that solved the issue. I tried re-installing the audio driver from Realtek's website, updated through driver installing software etc.. with no avail. I am not willing to refresh/reset my PC, as it will remove many huge games and/or programs that I'm not willing to re-download.
Any help would be greatly appreciated.
EDIT: I fixed the issue by uninstalling Razer Surround Pro, and everything is working perfectly (For now).
How I found out it was/could be the cause: I opened up services, searched for the windows audio service and audio end point builder, right clicked audio end point builder, clicked properties, then went to it's dependencies, and expanded the audio service to see what's under it. I thought I'd uninstall Razer Surround to see if it fixes the problem, and it did. Rebooted the system to see if it comes back, and it didn't. The CPU usage is finally back to normal.
My guess is it was conflicting with the audio driver.