Monday, January 15, 2007

Overclocking the BFG 8800GTS

BFG Technologies' specifications for the BFG 8800GTS are: Core Clock of 500 MHz, Shader Clock of 1200 MHz, and Memory Clock of 1600 MHz. Everest Ultimate shows the actual specifications of my BFG 8800GTS as: Core Clock of 513 MHz (better), Shader Clock of 1188 MHz (worse), and Memory Clock of 1584 MHz (worse). I got a little more speed with the processor and a little less with the memory speed, but pretty close to factory specs.

BFG Technologies now also markets a BFG 8800GTS OC (Overclocked) version which increases the Core Clock to 550 MHz and the Shader Clock to 1300 MHz. These are my initial overclocking targets plus increasing the Memory Clock to its spec speed of 1600 MHz. I set the Core and Memory clocks to these values in ATITool 0.26 and started testing for stability, i.e., "Scan for Artifacts." Note that the Shader Clock is linked to the Core Clock. Also note that Everest Ultimate does not appear to show the same clock speeds as ATITool 0.26.

I allowed ATIT00l 0.26 to "scan for artifacts" for over 4 hours while closely monitoring the GPU temperature which is 54C @ idle. The image on the right is a screen capture at just over 2 hours of scanning for artifacts with no errors. Note that the GPU temperature is at 61C. The GPU temperature would spike up to 62C once in a while, but it never exceeded 62C. After over 4 hours of scanning for artifacts, ATITool 0.26 detected no errors.

Next, I ran the Nvidia 8800 demos (Smoke, Adrianne and Froggy) for an extended period to visually check for artifacts and to observe GPU temperatures. The Froggy demo exercised both the CPU (96-100% utilization) and the GPU. While running the Froggy demo, the GPU temperature peaked at 65C/149F, the CPU temperature peaked at 53C/127F, and the motherboard temperature peaked at 30C/86F. These temperature readings are all within acceptable range and I also did not observe any artifact problems.

How well does an overclocked Nvidia 8800GTS perform?

Quite well.

I fired off 3DMark06 and Nighthawk scored 8747 3Dmarks compared to the 8409 3Dmarks scored without GPU overclocking, an improvement of over 300 3Dmarks! Keep in mind that the 3DMark06 benchmark is primarily used for graphics performance so this result was to be expected. Here's the 3DMark06 comparison.

I might be able to hit the 9000 3Dmarks score yet.

I concluded my stability testing by flying between Caribbean islands in Flight Simulator X. I am happy to report that the scenery was perfect (no artifacts) and excellent. I also had one of my best landings ever.

My next overclocking target is to inch closer to the Nvidia 8800GTX specifications. I have already increased Core Clock to 575 MHz and the Memory Clock to 850 MHz. ATITool 0.26 has been scanning for artifacts since almost 2 hours ago (with no errors so far) as I write this post. I will report the full results tomorrow.

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