Orijinal gönderinin sahibi: JEdeS ,
Getting the same issue with an iMac using this GPU. It started right after upgrading the OS to Lion. Unplugging the computer for at least an hour "fixes" the system temporarily as it resets the SMC. Issue comes back and gets progressively worse over the course of a few days. For me, downgrading back to Snow Leopard was the "fix".