7870 Litecoin/Scrypt - Can't get above ~280

[nightengale]

Trying to help someone get a little more out of his 7870. I'm running...

cgminer.exe --scrypt -o <site> -u x -p x -v 1 --worksize --lookup-gap 2 --thread-concurrency 8192 -g 1 --intensity 13

GPU clock 1103
MEM clock 1450

This is a Win 7 x64 system with 16 GB RAM and the 7870 is the only card in the box. Using Catalyst 13.1.

If I go above an intensity of 13, I start to get hardware errors.
If I set thread concurrency above 8192, cgminer won't start.

I'd like to figure this out, because it could have easily been me who bought the 7870... 

[Spetznaaz]

Try using -g 2 with -I 13.

Also, try decreasing GPU clock speed by about 25Mhz in both directions - see which one results in increased hashrate and which result in decreased hashrate - then continue in that direction by 1-2Mhz at a time, eventually the hashrate will suddenly drop, back up a couple Mhz and that should be the sweet spot.

ALso try: -s 2 --expiry 1 --queue 0 --thread-concurrency 8192 -I 13 -w 256 -g 2

Let me know what happens.