GeForce 6800 Ultra PCI Express: Have You Ever Heard a Rocket Launch?

NVIDIA Corporation was kind to offer us a couple of high-performance GeForce 6800 Ultra graphics cards for our tests:

Externally, the GeForce 6800 Ultra PCI Express differs from the GeForce 6800 GT in the design of the cooling system alone. It takes two slots and is analogous to the one we saw on the reference AGP-interfaced GeForce 6800 Ultra sample we described in our article devoted to the announcement of the NV40 GPU (see our article called NVIDIA GeForce 6800 Ultra and GeForce 6800: NV40 Enters the Scene). There’s a small, but important nuance, however. The GPU heatsink in the first revision of the cooler had been made of aluminum, but the company later changed the material for copper, to improve the cooling efficiency. In all probability the GeForce 6800 Ultra will use a copper heatsink henceforth.

Besides improving on the GPU cooling system, the shape of the heatsink that cools the components of the card’s power circuitry has been changed. It has become bigger, with more ribs. They must have thought the heatsink of the older type insufficiently good.

Launching a system with two installed GeForce 6800 Ultra graphics cards was not unlike launching a space shuttle ?you shouldn’t be nearby at either of these events unless you want to lose your hearing. This pair of cards produced enormous noise, and what was particularly disgusting they wouldn’t slow down their fans after the OS was booted up, like GeForce 6800 Ultra/GT cards usually do! Of course we had to brace ourselves up and run our full cycle of tests under such conditions, but we don’t think home users are going to appreciate that. Our checking with the help of RivaTuner showed that the cards were working at 437/1130MHz frequencies (GPU/memory), and that was considerably higher than the normal frequencies of the GeForce 6800 Ultra graphics card.

We found out later that the problem with noise and frequencies only showed up on the nForce4 SLI platform. When installed separately into an i925-based system these graphics cards behaved quite normally, reducing their fan speeds at OS’s boot-up and working at the regular 400/1100MHz frequencies. At the moment of our tests the ASUS A8N-SLI Deluxe mainboard had had BIOS version 1003-001 Beta dated 30.11.2004, but the problem persisted even after we had updated the BIOS to version 1002 Final and installed the latest version of the ForceWare driver.

We are not sure what’s the root of the above-described problem, and we just hope end-users won’t meet it. We guess there would be few people who’d like the idea of wearing protective headsets before their computers.