For now we can only overclock the HIS Radeon HD 5850 using the ATI Catalyst Control Panel, which is fairly limited in scope, so we are not exactly sure how far it will go in reality. The application allowed for a maximum core overclock of 6.5% while the memory could be boosted by 11%.

Needless to say the HIS Radeon HD 5850 easily handled this mild overclock. We expect it to crack the 800MHz barrier once better software is available, but even so our limited overclock allowed for decent performance gains at different resolutions, as you can see from the graphs above.