How do I reduce desktop window manager GPU usage?

Hi all,

Currently I'm using a Dell XPS 9560 (i7-7700HQ, 16GB RAM, 512GB SSD) and it was running fine before I update my Windows.

Now I have a high GPU usage issue with Desktop Window Manager (dwm.exe) & Client Server Runtime Process (csrss.exe). Here are some symptoms:

• Drag a browser around (IE, Chrome) will make Desktop Window Manager's GPU usage increased to 25-30%.
• Play any game will make those processess' GPU usages increased a lot (sometimes it will used up 100% GPU).

I've both Kaspersky Internet Security 2018 and Malwarebytes Premium installed. Did some full scans but there was no issue at all.

I thought maybe there was a bitcoinminer was running so just to be safe I've done a clean Windows installation (downloaded the latest Windows 10 ISO from Microsoft, used diskpart to clean everything) but the problem still persists which annoys me a lot.

Does anyone have this problem as well? Is there a way to fix this?

Many thanks