Diamond Viper Radeon HD 3850 512MB Ruby Edition
Overclocking Results
As we've already mentioned, ATI's original specs for the Radeon HD 3850 called for 256MB of onboard memory with core and memory clock speeds of 670MHz and 830MHz, respectively. The Diamond Viper HD 3850 Ruby Edition comes pre-overclocked with speeds of 725MHz for the GPU and 900MHz memory. That extra boost in speeds give's Diamond's offering a nice increase in performance over reference cards, but that didn't stop us from seeing if we can get any further. Doing so doesn't require anything other that the Catalyst drivers themselves. We clicked on the Overdrive tab in the Catalyst Control Center, and slowly raised the core and memory speeds until we either saw visual artifacts while running a game or benchmark, or noticed any other system instability.
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The Diamond Viper HD 3850 comes with an oversized heatsink requiring two slots rather than one. This extra bit of cooling helped us achieve speeds of 760MHz for the GPU, 35MHz over the shipping speed and 90MHz over spec. Memory was also raised to a top speed of 975MHz, an additional 75MHz over the packaged model, and a plus 145MHz overall. We re-ran a couple of gaming benchmarks and compared the frame rates with the original tests:
Diamond Viper HD 3850 Overclock - GPU=760MHz, Memory=975MHz (1.95GHz DDR)
Diamond Viper HD 3850 Overclock - GPU=760MHz, Memory=975MHz (1.95GHz DDR)
The extra speed increases resulted in about three frames per second in either game, each running at 1600x1200 with 4X AA enabled. While this didn't make much of a difference when comparing the HD 3850 to NVIDIA's camp, it did help distance the Diamond version from Sapphire's stock model, and ultimately brought performance much closer to that of an HD 3870.
