I've hated this card since I got it. All my other 280x's would easily get above 700 kh/s, but the XFX just wouldn't. High 500's or into the 600's on a good day.

I messed around with everything. Threads, concurrency, engine clock, memory clock, undervolting, you name it. It just hated me. In return, I hated it. With a passion. It was known as the "fucked card" in my house.

Temps were real good, so I never worried about that too much. Until today in desperation I hooked up a large table fan blowing on the rig.

Now, despite this, the internal fan read about the same speed and working temp in cgminer was the same.

But now I was up over 700. Easily. Suddenly. With a bit of tweaking I'm now getting 730 no problem. Maybe I'll get a bit more with more tweaking.

So, it was temperature related. Despite all indications otherwise.

So for those of you (I know there's a few; I've seen the posts) tearing their hair out over their XFX 280X "fucking cards," cool that fucker. Cool the shit out of it. Then cool it some more. Then actually stop fucking around and really cool it.

Then, set it at g 2, concurrency 8191, mem 1500, engine 1060, I 13, the 040 bios, and then watch the magic.

EDIT: Yes, TC of 8191 and, oddly, worksize of 64. Those seem to get me the fastest hashrate.