It is a known flaw that some models of the Radeon HD 4800 accelerators fail oZone3D FurMark, an OpenGL based graphics benchmark application that has found to stress Radeon HD 4800 series far enough to result in over-heating, artifacts or even driver crashes. The Catalyst 8.8 drivers have found to treat the FurMark executable differently based on its file-name.

Expreview tested this hypothesis by benchmarking a reference design HD 4850 board using Catalyst 8.8 driver, with two runs of FurMark. In the first run, the test was cleared at a low score, much lower compared to those of whatever successful runs on older drivers could churn out. Suspecting that the driver could be using some sort of internal profile specific to the FurMark executable, Expreview renamed the furmark.exe file, thereby not letting the driver know it's FurMark that's being run.

You can read the entire article at TechPowerUp.