A770 on ultrawide glitches half of the screen with freesync, doesn't detect rebar

Pepijn · ‎03-25-2023

I have an Intel ARC A770 GPU on an ASUS X670E-PLUS motherboard with AMD Ryzen 7950X CPU.

I have updated all my drivers and firmware and rebar turned on in the bios, which is detected correctly by GPU-Z and works as expected under Linux.

However, under Windows 11, the right half of my ultrawide monitor is completely glitched out, and choosing a smaller resolution doesn't fix this.

What does fix the glitching is turning off AMD FreeSync on my monitor, which is not ideal.

I'm primarily using Linux so it's not an immediate deal breaker but it is of course pretty useless if I want to play a game or something. If I were a Windows user I'd be returning the card, so I really hope yall get on top of these driver issues.

Pepijn · ‎03-27-2023

So I've done some more digging and experimenting. Disabling SVD fixed the rebar issue, which is really a no-go as I use docker a lot for work and barely use windows. As mentioned the display glitch seems to be a bug in the driver concerning AMD freesync on ultrawide monitors.

community.intel.com/t5/Intel-ARC-Graphics/resizeable-bar-display-is-not-enabled-in-arc-A770-with-MAG-B550M/m-p/1469738#M2698

Now that rebar works I thought I could maybe test performance a bit, but the first game I tried, Trackmania crashed right away. I only managed to run it with DXVK which I've read isn't representative in terms of performance. So I continue to be unimpressed by this graphics card when it comes to windows drivers.

On Linux it's been smooth sailing so far, fingers crossed.

Saveno · ‎03-27-2023

I believe it is just a visual bug. I also had to disable Virtualization in Bios, before the Control Panel said ReBar is not enabled, but the performance in benchmark was the same. As long as "Large Memory Range" shows on Device Manager > Arc770 > Resources ReBar should be enabled and it also shows it when Virtualization is activated. Just do a Benchmark with it being disabled, then enable it and do another Benchmark and the results should be the same.

SlothRider · ‎03-27-2023

Does the glitching only happen with your UItrawide? Do you have any other monitors connected when it happens, and if so, do they ever similarly glitch?

I've experienced the same issue with my Arc A770, though my circumstances are a bit different. I have a Samsung S34J55 WQHD as my center monitor, with a Dell P2417H FHD on the left and right. Only the left P2417H would ever glitch like in your screen shot.

Simply turning off and on any one of the monitors long enough for the desktop to settle on the other two screens, then turning it back on was enough to correct the issue. Internally, I don't know if it was restarting the graphics driver, reinitializing the desktop on the available displays, or what.

I tried different driver versions, completely removing between versions (Clean Install option in the installer as well as Display Driver Uninstaller) and swapping ports on the card. The problem always was still with the left monitor. My monitor cords were ran in my monitor arms and are a pain to remove, and I didn't have a spare DP cable long enough, so I never swapped display cables.

I lived with the glitching as it only took a couple of seconds to "fix" and it didn't happen all the time. I recently did some rearranging and needed to get a longer cable for the left monitor. After replacing the old cable with a slightly longer one, the glitching like what you showed has gone away.

I have experienced some other seemingly GPU related issues that require an occasional Win-Ctrl-Shift-B restart of the drivers. Explorer needs to be restarted about as often to fix some taskbar issues. Neither problem I experienced prior to getting the A770, but I've made other changes about the same time. It still feels like a GPU driver issue, but I can't definitively blame the A770 at the moment.