Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Sometime ago I replaced my HD 4850 graphics card with a HD 7750. Since then, I am experiencing something like a snow effect: slow vertical tiling and quick, flickering white pixels running on the screen (looking closely it's visible everywhere, but generally noticable on dark backgrounds), just like on an old TV. The interesting thing is, it does not occur with every application, but mostly games (for example Mass Effect 3, all Source games, Deus Ex: Human Revolution, even the Steam platform itself). The problem is not visible on screenshots or videos.

I tried another cable and an another monitor, and while the problem was still there, it became almost unnoticable. Also I tempered with the graphical settings and disabling vertical sync makes it much worse, the games mentioned above have became almost unplayable. I'm not sure how this one would be connected to vertical sync.

I also tried to reproduce the problem on my Arch Linux, but I couldn't. As testing the games is rather difficult with the vesa driver (catalyst somewhy performs much, much worse), I could only try Steam in wine, but no snow effect there. I even tried an another, clean Windows 7 installation, but the problem persists on Windows whatever I do.

I really can't figure this one out, sounds like a definite software problem, but internet searches show nothing. Any thoughts?

share|improve this question
up vote 2 down vote accepted

What effect do your PSU have? Do you have a lot of disks, drives or other kind of modifications that takes power from the system.

About vertical sync. It's actually limiting your graphics card to what your monitor can handle. So if you have it active on a 60hz monitor you limit the output from the card to 60fps. Disabling vertical sync in games will put more pressure on your gfx and system.

share|improve this answer
No, not really. I disconnected all unnecesarry components for a try, but not a change to the problem. – salla Aug 12 '12 at 10:14
But you are sure your PSU is strong enough? Sorry if it's a silly question. – Hoshts Aug 12 '12 at 15:15
No need to apologise, you are trying to help :) On the other hand, I am fairly certain it's not a power related issue - according to the specs, my PSU matches the card's recommendations. – salla Aug 12 '12 at 22:29
I know it might be a bit of work but you could, if possible, try the card in another computer. If the problem would show on that computer as well I would suggest contacting the retailer for a replacement card. There is always a possibility of a production error or software error on the card as it more or less only show when you start a game. – Hoshts Aug 12 '12 at 22:40
Thank you for your answer - I managed to get my card into an another PC which did not have the problematic applications installed, but one game there reproduced the problem. – salla Aug 15 '12 at 12:40

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.