![[H]ardOCP](/images/blank.gif){kind=small}
- Date:
- Tuesday , February 01, 2005
- Author:
- Brent Justice
- Editor:
- Kyle Bennett
- Google +1
Gigabyte 3D1 GeForce 6600GT SLI
NVIDIA SLI on one video card? It is possible, and Gigabyte shows us how it’s done. See how the Gigabyte GeForce 6600 GT SLI stacks up to the competition and find out which is better performing -- a 6600 GT SLI solution, or a single GeForce 6800 GT.
Introduction:
Dual core video cards are nothing new. Back in their prime, 3DFX succeeded in producing gamer-oriented video cards with multiple cores and chipsets. The famous Voodoo 2 and 5 were all multiple chip configurations. The Voodoo 2 was composed of one Pixelfx2 and two Texelfx2 chips on board that allowed it to do multi-texturing. The Voodoo 5 5500 contained two VSA 100 graphics cores on one board connected via SLI (Scan Line Interleave).
With the Voodoo 2, you could increase performance by installing two of these cards in what was then also known as SLI (Scan Line Interleave) and enjoy higher resolutions with more performance. The epitome of Voodoo 2 SLI was the Quantum3D Obsidian 100SB and 200SB i.e. Obsidian2 X-24. Quantum3D upped the ante by taking two or more Voodoo 2 video cards and integrating them into one board. When the Voodoo 5 arrived, 3DFX implemented a multiple core configuration like the Obsidian with the cores connected in a digital SLI (Scalable Link Interface) link. This is exactly the kind of integration we are seeing here today with NVIDIA’s SLI and two GeForce 6600 GTs for the first time.
Remember, 3DFX’s SLI and NVIDIA’s SLI are two completely different technologies. The only likeness they share is the idea of increasing performance using multiple video cards, and the fact that the name for the technology can be made into the same acronym. 3DFX’s SLI stood for Scan Line Interleave and operated by having one card (or one chip) render the odd number of lines on the screen, while the other card (or chip) rendered the even number of lines on the screen. NVIDIA’s SLI stands for Scalable Link Interface and has two different modes of operation. One mode is Alternate Frame Rendering (AFR) where one card renders one frame, and the second card renders the next frame. The other mode is Split Frame Rendering (SFR) where the cards load balance portions of one frame between both cards at the same time. NVIDIA tests to see which mode works best in individual games and then programs this into game profiles in their drivers. Therefore, SLI operation is completely transparent to the end user. You just enable SLI in Windows, and off you go.
To read all about NVIDIA’s new SLI, you can check out our preview of it here. You can also check out our SLI Upgrade guide where we compared all of the NVIDIA SLI capable video cards in three popular games to see what SLI can do for you.
Just as Quantum3D upped the ante with the Obsidian dual Voodoo 1 and dual Voodoo 2 cards, Gigabyte is here to up the ante with NVIDIA SLI. However, there are some limitations. The first limitation is that Gigabyte is introducing the Gigabyte GV-3D1 as a packaged deal. They are creating a motherboard and video card bundle with their K8NXP-SLI motherboard. The only way you can get the 3D1 video card is to buy the motherboard package. They are strapped together like two peas in a pod. The complete bundle will be sold for $550 USD. The other limitation is that Gigabyte claims the 3D1 can only be used with the K8NXP-SLI motherboard because it requires a special BIOS to recognize the 3D1 video card. We will explore this limitation on the next page.
So what exactly is the Gigabyte GV-3D1? If you hop on over to Gigabyte’s webpage you will see they have a page up showing you the specifications. Unfortunately, these specifications are a little misleading. Although the Gigabyte 3D1 is comprised of two GeForce 6600 GT GPUs on one board, it does not mean the memory is a shared 256MB framebuffer on a 256-bit memory bus. What gigabyte is doing here is simply adding the fact that there are two sets of 128MB memory for each GPU and adding the memory bus width. In fact, the total framebuffer is still only 128MB – the same as putting two 128MB GeForce 6600 GT video cards in SLI. Furthermore, the memory bus is also still a 128-bit memory bus, just as it would be putting two physical GeForce 6600 GT cards in SLI. This video card does require a PCI-Express x16 slot and does use all 16 lanes split up by 8 lanes for each GPU.
With the GV-3D1, Gigabyte has taken two GeForce 6600 GT GPUs with 128MB of memory and placed them on one board connected via SLI. You can see the kind of performance we experienced with two physical GeForce 6600 GT’s in SLI on an Asus A8N-SLI motherboard here.
The Gigabyte 3D1:
Gigabyte ships this motherboard and video card bundle in a two box set with handles that unfolds. Inside each side is a separate box containing all the goodies.
In one box, you’ll find the motherboard and all its parts. In the other box, you’ll find the dual power system and the wireless adapter, and underneath this box you will find the video card, cables and software CDs.
Here you can see that this card is a single-slot video card, despite it having two GeForce 6600 GT GPUs on board. Gigabyte is using a blue PCB where both GeForce 6600 GTs are placed. The all copper heatsink covers both GPUs with dual fans to keep it cool. Each GPU is surrounded by 128MB of RAM with a four module configuration for each GPU. The video card does not have an SLI connector on the top of it, so no luck plugging in two of these to equal four GPUs (sorry to ruin your dreams there).
This video card draws more power than a single GeForce 6600 GT which on its own does not require external power for the PCI-Express version. The Gigabyte 3D1, with its two GPUs, does require external power, however. Therefore, Gigabyte has integrated the 6-pin PCI-Express external power plug. You must plug this in for proper operation. At first glance, you would think the heatsink is actually touching the RAM helping to cool it. However, upon closer inspection, the heatsink is just hovering over the RAM with no contact made between it and the RAM modules. The Gigabyte 3D1 comes with a video out port, and the standard DVI and VGA connectors.
We won’t go into detail on the motherboard here, since the focus of this article is on the gaming experience with the video card. Here is a picture of the motherboard, and you can read the full specifications on it here. One thing to note is the closeness of both PCI-Express slots to each other. They aren’t as spread apart as the ones on the Asus A8N-SLI, which could make installing dual slot video cards such as the 6800 Ultra in SLI, interesting. Furthermore, if you did install two 6800 Ultras on this board, SLI heat-related issues could be even worse than normal due to the close proximity of the PCI-Express slots.
To operate the Gigabyte 3D1 video card, you must have the motherboard slot connector set to Normal Mode. In Normal mode, all 16 lanes are available for the primary PCI-Express slot. If you set this connector to SLI mode, then only 8 lanes are available for each PCI-Express slot and that won’t be enough for the Gigabyte 3D1 video card. The Gigabyte 3D1 video card splits up each GPU by 8 lanes, so it must have all 16 lanes available on the primary slot. If you are installing two SLI capable video cards on the motherboard, one in the primary slot and on in the secondary slot, you must flip the card around to SLI Mode.
When we installed the Gigabyte 3D1 in the K8NXP-SLI motherboard, we noticed that it rests against the motherboard’s chipset heatsink fan unit. Although this didn’t cause any problems for us, it is worth noting nonetheless.
Included in the package are two games, Joint Operations Typhoon Rising and Thief, and a driver CD. ForceWare drivers 66.93 and up support SLI and you can use reference NVIDIA drivers from their website. Gigabyte includes a PCI-Express power cable, a DVI to VGA adapter, and a breakout box with video output connections.