To overclock the ATI Radeon 3870 HD video card, I used ATI Overdrive that is part of the CATALYST Control Center. When you ‘unlock’ the ATI Overdrive, you can manually set the clock and memory settings or let the ‘auto-tune’ utility to set the frequencies for you. Just for fun, I tried out the auto-tune feature to see if it could really find a stable clock configuration for the Radeon 3870 HD and it would lock up the system. I then manually increased the clock settings for both the core and memory to reach the highest stable overclock. Let’s see what the Radeon HD 3870 can do!
After ATI Overdrive finished, it showed the clock speeds being 850MHz on the GPU and 1351MHz on the memory. This is a nice jump up from 777MHz/1126MHz, which are the stock settings. Once I started to play games with these overclocked settings, the system was found to be stable. Let’s take a look at see what this overclock did on a couple games.
In the DirectX 10 game title Crysis a 3 FPS increase was noted and in the DirectX 9 game S.T.A.L.K.E.R. a 9 FPS boost in performance was seen again. It looks like our overclock got us a solid frame per second increase, which isn’t bad. The extra 73MHz on the core and 224MHz on the memory make for a nice clock rate increase and the performance shows it!