We set out to raise each speed until we reached any kind of instability, benchmark crash, or other artifacting noticeable on screen. Starting out at 740 MHz, 1836 MHz, and 1100MHz, respectively, we bumped the speeds up one component at a time until we either crashed or saw graphic anomalies in the benchmark routines. With the extravagant cooling provided on the ECS Hydra, we hoped for some big numbers since temperatures would be held in check.
840 MHz was as high as we could get for the GPU. A 100 MHz overclock doesn't sound all that great until you realize that the 9800 GTX+ is really just an overclocked 9800 GTX to begin with. Specs for the 9800 GTX call for a 675MHz clock speed, so our 840 MHz can actually be thought of as a 165 MHz boost. Shader clock speeds topped out at 2071 MHz, a 235 MHz increase, and the memory at 1250 MHz (2500 effective).
With our overclocked cards running stable, we decided to give 3DMark Vantage another run-through to see what kind of frame rate increases we might be looking at.
3DMark Vantage's GPU tests showed over a 4 frame per second advantage while overclocked, - roughly equivalent to a 12% increase in overall performance. We also measured temperatures while running at idle (37 degrees F) and while under load during our overclocking routines (44 degrees F), and saw only a 7 degree difference. Conclusion: We're running some of the fastest numbers in our benchmarks with the ECS GeForce 9800 GTX+ Hydra without the extra thermal challenges associated with higher clock speeds.