Disabling CSM in bios tanking GPU performance?

isaacr100

Junior Member
Nov 15, 2018
2
0
6
I recently noticed that my BIOS was running in legacy mode, and I wanted to switch it to UEFI mode because I originally thought it already was and I've read that it's better. So first I converted my HDD from MBR to GPT using the windows MBR2GPT tool and that worked fine. Then I went into my bios to look for the legacy/uefi setting, but my motherboard(ASRock AB350 Pro4) doesn't have an exact setting called that. The closest I could find was and option to disable/enable CSM. I read that CSM made the UEFI looks like a BIOS so it could boot from a BIOS OS, and that you should disable it if you are running windows 8 64 bit UEFI or higher, which I am, and now that I had converted my OS from MBR to GPT making it able to boot from UEFI, I disabled CSM. Everything worked fine until I went to play some games and noticed my FPS was significantly decreased. I have a 1050 Ti, and I went from 220 FPS in CS:GO to 30, and from 45 FPS in War Thunder to 8. I restarted, enabled CSM, and the FPS went back up to what it was normally at. Why would disabling CSM, which you should disable if your OS is UEFI and if you are on a newer OS, hurt your GPU?

Specs:
Ryzen 3 1200 @3.9 Ghz, @1.3V
ASRock AB350 Pro4
1TB Toshiba P300 HDD
Corsair CX550M PSU
Zotac 1050 Ti Mini
8GB(2x4) Crucial Ballistix Sport LT RAM @2800 Mhz
Windows 10 Pro 64-bit
 

isaacr100

Junior Member
Nov 15, 2018
2
0
6
MOBO manual:
Oh OK, I find that weird though since it says in the BIOS you should disable CSM if "You are using Windows 8 64-bit UEFI and all of your devices support UEFI." Maybe they made a mistake in writing that, anyway thanks for the help!
 

vailr

Diamond Member
Oct 9, 1999
5,365
54
91
The 1050 Ti should include UEFI support. That status can be double-checked via using the free software "GPU-Z". Other than that, try the complete re-format & re-install Windows procedure.
Note: if using a USB thumb drive for Windows installation, the thumb drive must itself be formatted and use the GPT format, for properly setting up a "pure UEFI" system. I recommend using the free software "Rufus" for creating the USB thumb drive Windows installation medium. That GPT thumb drive will only be bootable if CSM is first disabled in bios.
After Windows is re-installed, another free software "Iobit Driver Booster" may find some missing or updated device drivers.
Those free softwares can be found on majorgeeks.com.
 
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