I hope someone can help with this. I've no idea whats wrong...

Im using Windoows 7 64 bit and cgminer 3.5 and the following hardware
Mobo: ASRock Extreme3 R2.0
Processor: AMD Sempron
RAM: Patriot 4GB DDR3 1333MHz
PSU: Thunderbolt 1200W
Graphics: Gigabyte Radeon R9 290

I get a crazy high HW rate (100-3000) and a kh/s of 650-750 in cgminer when I use the settings below. In the pool a kh/s of about 20-100 shows up.
setx GPU-MAX-ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
cgminer.exe --scrypt -o stratum+tcp://east-us.megamultipool.com:80 -u user -p password -I 20 --temp-cutoff 95

If I remove all settings and just use the below then I get HW:0 but a hash rate of 10 kh/s
setx GPU-MAX-ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
cgminer.exe --scrypt -o stratum+tcp://east-us.megamultipool.com:80 -u user -p password

If i reduce the intenity to 13 then I get a hash rate of about 400 kh/s and a HW rate in the hundreds.

Thanks