I recently bought a new HD6570 to put in my system since my previous card overheated like crazy lol. When i put it in everything was fine. I downloaded the newest drivers. I noticed in AMD Overdrive though that the memory clock was at 500mhz and gpu clock was at 650mhz. also it says the fan speed is 0rpm. I have a fan and i can see it turning. also, the graphics card advertised as 1000mhz memory clock speed, so "overclocked" it to 1000mhz, when i did this my screen went all weird and i got a blue screen, i put it back to 500mhz, why does this happen?