[Using cgminer 3.7.2, windows 7 x64, latest official amd drivers. (did a full uninstall and reinstalled them again)]

Hello everyone,

A friend of mine and I (both new to mining) bought the same GPUs - Sapphire r9 290 tri-x OC. He has a decent hashrate (around 850), but I have a problem - whatever tweaks I make in the scrypt, there seems to be no change or whatsoever in the hashrate.
Using cgminer 3.7.2, windows 7 x64, latest official amd drivers. (did a full uninstall and reinstalled them again)

Here are my specs:

i7-4770k
sapphire r9 290 tri-x OC
asrock z87 killer fatal1ty
16 gb of ddr3 ram @1600mhz running in dual channel
Seasonic m12ii Evo edition 750w

Here are my settings:

Code:

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_OBJECTS_SYNC 1

cgminer --scrypt -o stratum+tcp://stratum2.flappycoinpool.com:3353 -u antonsgeorgiev.anton -p 01020102hs -g 1 -w 512 --lookup-gap 2 --thread-concurrency 24500 -I 20 --gpu-fan 90 --gpu-engine 947 --gpu-memclock 1500 --gpu-powertune 20 --auto-fan --temp-target 80 --temp-overheat 90 --temp-cutoff 95

I have tried numerous changes in all parameters - changing W, TC, I, Memclock, Engine, Powertune and regardless of the changes made my hashrate tops at 540 every time with any settings applied.

Am I doing something wrong, or the exact question is "What am I doing wrong?", cause there surely is something going on, which is messing up my hashrate.
Please note that my friend gets around 850 hashrate with the same settings above.

Regards,
Anton