I just installed a new Sapphire Radeon HD 7950 video card into my Mac Pro (5,1 mid-2012). It works great, except occasionally, perhaps once every hour or so, the screen flickers. By "flicker" I mean that the entire image becomes garbled for just a fraction of a second and then returns to normal. The card's single dip-switch is set for Mac compatibility. No other video card is installed and I'm only running a single 30" Apple Cinema HD Display.

Does anyone have any idea what might be causing these occasional "hiccups" and whether it is something that can be stopped?


The "hiccups" could be due to poor cables. Previously I have seen that result in these "flickers" that come randomly once in a while.

Replace the monitor cables with properly shielded, quality cables!

  • I hadn't thought of that. I will try and report back – Zac Imboden Sep 26 '18 at 0:42

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .