Hi Paul,
Thank you for posting your Microsoft Forums.
As per the issue description, I understand that “SettingSyncHost.exe” uses 25-30% of CPU which causes the fan to run at high speed.
“SettingSyncHost.exe” is the process that synchronizes your system settings with your other devices so that changing your wallpaper/color on one computer changes all your other computers. It also syncs your Internet Explorer, mail app, OneDrive, Xbox
and other useful apps settings.
I appreciate if you could answer a few questions:
1. Is your computer connected to any domain or work environment?
2. Are you using too many third party applications or games on your system?
Check if you can experience the issue in ‘Safe mode’; if safe mode works fine then set the computer to ‘Clean boot’ state to check for software conflicts.
Step 1:
Windows Startup Settings (including safe mode).
http://windows.microsoft.com/en-us/windows-8/windows-startup-settings-safe-mode
Note: This article is also applicable for Windows 10 tech preview.
Step 2:
Keep the computer in a clean boot status and check. If everything works fine after a clean boot, you can infer that some third party services are causing the issue. Proceed with the remaining steps to pin-point out the third party
service. After you figure out the issue causing program, you may have to update or install a latest version of the program.
How to perform a clean boot to troubleshoot a problem in Windows Vista, Windows 7, or Windows 8.
http://support.microsoft.com/kb/929135
Note: This article is also applicable for Windows 10 tech preview.
Note: Please go through the section:
How to reset the computer to start as usual after troubleshooting with clean boot of the Kb article to boot the computer in normal startup after fixing the issue.
Hope this information helps you. Please do let us know if you need further assistance, we’ll be glad to assist you