The G9 can be a pain in the butt. It really put a damper on the excitement of getting a 3090 after years of being out of stock.
I’m 99% certain it’s at fault. Without the KVM, things like enabling GSync in the OSD can cause it to lose the input connection from the 3090. And since you need a working input to change settings on a G9…
My old setup was rock solid:
- Titan Xp →
- 200cm L1 DP cable →
- L1KVM →
- 120cm L1 DP Cable →
- Samsung G9 (120 Hz w/ GSync enabled)
After I swapped the Titan Xp for the 3090, I had to do a silly, clean reinstall of the NVidia driver.
I never got it to work through the KVM with GSync. I’d get half a second of video before it’d lose input for 30 seconds to 5 minutes.
Using my 2nd PC to disable GSync, I was able to get video from the 3090 thru the KVM again, but with a random jitter every few seconds. It would glitch and shake/jump to the right consistently at 60, 120, and 240 Hz settings, but not at ~119.997.
I didn’t write down the exact Hz, but one time I opened adv adapter properties and something like 119.999 was selected with an option to change it to 119.997.
That made the screen shake disappear and everything was perfectly stable thru the KVM for a day or two, but the next time I tinkered that Hz setting went away and never returned.
Also, I updated the G9 firmware to M-T9545GGAA-1015.2 at some point, but nothing changed. For now, I’m having to bypass the KVM.