More Gigabyte 3D1
At least for the time being, Gigabyte says the 3D1 will only work on its nForce4 SLI motherboard. Perhaps it will also work with VIA’s K8T890 at some point in the future as well, but the company isn’t yet ready to solidify the card’s compatibility. And, despite the very unique implementation, you won’t need to use any special software to get the 3D1 up and running. NVIDIA’s reference driver set works just fine.
The card does require a somewhat different motherboard configuration, though. Rather than set the K8NXP-SLI to run in SLI mode, the 3D1 utilizes all 16 PCI Express lanes offered by a single slot and thus needs to operate in “Normal” mode. Nevertheless, Gigabyte still includes the NVIDIA SLI connector with the bundle just in case you decide to adopt more powerful 6800 Ultra cards down the road.
External power connection required on the 3D1
When you turn on SLI multi-GPU rendering in the NVIDIA driver, the single x16 slot is divided into x8 pathways, each of which is dedicated to one 6600 GT processor. While it’s nice to think that you could add a second PCI Express graphics card for even more expansive multi-monitor support, the fact of the matter is that by enabling SLI, you’re harnessing all 16 lanes available for graphics. Even without the feature turned on, it’s possible to run dual monitors through the onboard DVI and VGA outputs, but you can’t add another card to the mix. Gigabyte’s 3D1 will serve as your primary and secondary adapters at all times.
You should also note that, in SLI mode, all thermal monitoring is disabled. It probably isn’t as important as it would be on a dual GeForce 6800 Ultra system with gratuitous heat dissipation, but it’d still be a useful feature to see Gigabyte add into its V-Tuner software.
The bundled V-Tuner overclocking utility is complemented by Gigabyte’s @VGA BIOS tool that’s able to update the 3D1 should a fresh BIOS file become available. Also included is Thief: Deadly Shadows, Joint Operations: Typhoon Rising, and an I/O dongle that enables S-video and component output to an HDTV.
While independently setting the clock frequencies of two cards in an SLI setup often yields a modest increase in theoretical performance (though not necessarily real-world results, as seen in Brandon’s SLI preview), putting the two processors on a single board seems to detrimentally impact overclocking potential.
Using NVIDIA’s built-in CoolBits registry modification we were able to get the 500MHz chips up to 525MHz, though they crashed in Doom 3. Subsequent attempts at overclocking resulted in the board failing NVIDIA’s mandatory speed test. Even Gigabyte’s V-Tune utility failed to extract extra speed. We’re hardly worried, though; juicing the traditional SLI setup didn’t yield much in the way of tangible gains, and so we weren’t expecting much from the 3D1 in that regard.