[SCRYPT-N] Help with settings! (to improve hashrate)

[Sapphires]

I'm using a PowerColor 7950 and only getting about 200 KH at 12 intensity right now, and so far every time I try to raise my intensity past 12, I get a bunch of HW errors.

Current settings: (with latest Vertminer)

Code:

setx GPUMAXALLOCPERCENT 200 
setx GPUUSESYNCOBJECTS 1 

Vertminer.exe --scrypt-vert -o stratum+tcp://eu.hashing.at:3021 -u Sapphire.Sapphire -p x -s 10 -E 30 -Q 1 -w 256 -I 12 -g 2 --lookup-gap 2 --gpu-powertune 20 --gpu-memclock 1500 --gpu-engine 1070 --thread-concurrency 6912

I've tried a tc of 8192 before, and it's about 10 KH lower on average.

I also have dual-bios so perhaps I should try to flash my card to a Sapphire/Gigabyte 7970 GHZ?

Any advice would be appreciated.