This thread was in the altcoin thread but got burried and it keeps coming up SO if you know what you're doing and are still getting crap performance from a 7970/280x then the problem is actually memory timings which in some cards its simply horrible.
There was also recent talk about RAM speed between 1250/1500 and this is SPECIFIC to these models. When RAM timings in the BIOS are set properly 1250/1500 will produce the same.
What you do is search the thread to see if he's already covered your model THEN if you don't come across it then you post your existing BIOS file.
https://litecointalk.org/index.php?topic=12369.0
he then edits the BIOS for ya and if you can you donate some change to the guy. The first "crap 280x" I did instantly got over 700 when it was down in the 500 range before. I've been meaning to do the rest but just haven't had a chance to yet. I wasted too much time rearranging my rigs yesterday and trying to find a way to get more out of the other cards like those 7850/7870's that are suck down around 300 (still)
There was also recent talk about RAM speed between 1250/1500 and this is SPECIFIC to these models. When RAM timings in the BIOS are set properly 1250/1500 will produce the same.
What you do is search the thread to see if he's already covered your model THEN if you don't come across it then you post your existing BIOS file.
https://litecointalk.org/index.php?topic=12369.0
he then edits the BIOS for ya and if you can you donate some change to the guy. The first "crap 280x" I did instantly got over 700 when it was down in the 500 range before. I've been meaning to do the rest but just haven't had a chance to yet. I wasted too much time rearranging my rigs yesterday and trying to find a way to get more out of the other cards like those 7850/7870's that are suck down around 300 (still)