A friend and I recently won an auction for a pair of identical EVGA GTX 295 graphics cards. Both cards work fine so we each put one in our media PC's. The systems are fairly equally matched so we tend to trade blows on benchmarks. With these cards, however, mine gets nearly double the FPS on the Furmark benchmark that his does. After some fiddling around we discovered that the problem seems to be with the fact that his is connected to his display using HDMI and mine is connected using an HDMI-DVI cable.
If I connect my display using the HDMI port on the card, my frame rates drop almost exactly in half. Likewise if he uses DVI, his framerates nearly double. It behaves as if when using the HDMI output port (no other displays connected), the card does not truly perform in SLI. In fact disabling SLI will get the same frame rates as using the HDMI port. The funny thing is that with SLI enabled, Furmark shows both GPU cores running at 99% while the benchmark is running but the performance is the same as running with SLI disabled which Furmark only shows as taxing one core.
My friend would really like to use the HDMI output AND get full performance out of the card. Is there any known way to make this happen? I guess I should mention it's running windows 7 x64