Im having to lower my 4890's clock speed to stop it crashing my PC im sure its the Gpu causing my crashes cos i tried everything and the only time i stopped crashing was when i lower the clocks on GPU, the only reason i remembered is because i reinstalled win 7 over the wknd and i my system started crashing again obviously id forgotten to under clock the card again but now i have its stopped works fine untill its under load only underclocked by 10 mhz on both mem and core so would this b classed as faulty and replaced?