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GeForce 6800Ultra Preview

We test the reference GeForce 6800Ultra (NV40) comparing it to a GeForceFX 5950Ultra and an ATI Radeon 9800XT. We focus on pure gameplay performance and image quality.

Introduction:

Today the wrapping comes off the box and NVIDIA's GeForce 6800Ultra (codenamed NV40 GPU) video card is revealed. To learn all about what's new in the NV40 please refer to our NV40 tech article. That article will tell you about the new features and what they mean. Remember that the NV40 technology will encompass a whole range of cards from the value market to the enthusiast market. The only feature difference between these cards will be regulated framerate performance by reducing core clock frequency, memory frequency, and also reducing the number of pixel pipelines to reduce transistor counts in order to bring down silicon costs. This new series is called the "GeForce 6" series. The specific video card NVIDIA has provided to us for this preview is the GeForce 6800Ultra, the highest level of the GeForce 6 series GPU currently. This article is a preview, not a review, since this is a reference video card from NVIDIA and cannot be purchased through the normal channels. That said, every GeForce 6800Ultra video card from retail partners should perform very closely to what we are showing you here today on a comparable system.

Here is a quick rundown of new features in the NV40. It adds complete support for Microsoft’s DirectX Shader Model 3.0. To read about the improvements in Shader Model 3.0 over Shader Model 2.0 please read here. This is really the biggest improvement for developers, which will allow them the room to make games the way they want to, with little limitation. The NV40 comes packed with 16 real pixel pipelines capable of performing 16 single texture pixels per clock color and Z and 32 pixels per clock Z only along with 6 vertex shader units. This can be called 16x1/32x0 if you need to look at it in that format. Everything combined comes out to be 222 million transistors packed into a 130 nanometer core fabricated at IBM.

Three of the biggest image quality concerns we will look at today have also been addressed in the NV40. The shader precision is full 32bit floating point across the pipeline and is said to have been vastly improved in performance so that games can run at full 32bit floating point precision, unless a content developer sees the need to drop to FP16 which is still an option. There is no FP24 support as some rumors have circulated regarding that. Another improvement is in the Anti-Aliasing sample pattern the NV40 uses. The NV3x series used an Ordered-Grid sampling pattern, and the NV40 uses a Rotated-Grid pattern. The filtering capabilities have also been changed; there is now support for up to 16X (128-tap) Anisotropic Filtering with an adaptive algorithm. We will be comparing image quality in each game.

Of course there are a myriad of other improvements, which our tech article will cover in much more detail if that interests you. Here in this article we are going to focus tightly on what exactly a GeForce 6800Ultra can deliver in terms of playability when gaming.

The GeForce 6800Ultra video card we have for preview today is an AGP8X version. There will be PCI-Express versions of NV40 in the near future. With NVIDIA’s HSI technology they will be able to easily adapt AGP8X cards to PCI-E and vice versa. When we have a PCI-Express video card and a PCI-Express motherboard we will examine NVIDIA’s HSI technology and see how it impacts performance, if at all.

The GeForce 6800Ultra:

The GeForce 6800Ultra runs at 400MHz core and 550MHz (1.1GHz GDDR3). The GeForce 6800Ultra is a two-slot solution, in this instance meaning that the heatsink unit on this card expands over the adjacent PCI slot. In the past this had conjured up thoughts of a very heavy video card, however, the HSF is very light thanks to its aluminum composition. In fact, the weight of the video card is less than the GeForceFX 5950Ultra reference card. It just looks a bit heftier than it actually is.

Looking down you see the HSF rises 1 inch or so off of the GPU. In the picture above you can see there is very little room in between the two cards for the video card to draw air in to keep it cool if there is a card in the adjacent PCI slot. It is our suggestion that you give any video card as much room to breathe as possible. With this in mind, our motherboard (ABIT IC7-G) goes down to 3 useable PCI slots. This is of course going to vary from motherboard to motherboard and also hinge greatly on how cool the inside of your computer case is kept.

You have by now noticed the two Molex connectors. One is labeled "Primary," but both are required to be plugged in if you want to run this video card at full clock speeds. The round device next to the Primary Molex connector is a temperature warning speaker. We used our normal 431 Watt Enermax Power Supply on our test bed and it worked flawlessly with the video card. Note that we don’t have any other wild power draining devices though, simply one CDROM, Hard Drive and Floppy Drive, a very basic setup. We will do more testing on power consumption levels as retail cards come to market.

Our card is using 256MB of 2ns Samsung GDDR3 SDRAM rated at 500MHz. So the fact that the memory is running at 550MHz by default means it is "overclocked" past its rated speed for these modules. Looking at Samsung’s website we find that that there are faster modules in this series. It seems there are GDDR3 modules from Samsung capable of running at 1.25ns delivering 800MHz. So the future looks bright with the possibility of seeing faster chips out there.

In the second picture above you can see that our card is using the NV40-A1 core, which is the first revision core that NVIDIA went into production with. This alone is a good sign that NV40 has been done "right."

As you can see this card is using dual DVI. We are very happy to finally see this come to today's desktop video cards, and we hope to continue to see retail cards with this feature although assuredly all will not. Gigabyte has announced their flagship 6800Ultra, and it shows to have dual DVI outs.

Our card has an interesting workaround in place on the reverse side of the power connector for the fan in the heatsink. We don’t know exactly why or for what reason it's there, but it was worth noting.

In the first picture above we have compared the GeForce 6800Ultra to an ATI Radeon 9800XT. As you can see the 6800Ultra is a bigger card. The comparison to the GeForceFX 5950Ultra in the second picture is more interesting. The actual lengths of both cards are exactly the same at 8.5 inches long. The height is slightly different with the 5950Ultra being slighter higher due to the second case slot bracket.

Lastly, here is our GeForce 6800Ultra in real action!

Note that both Molex plugs are coming off of one wire from the PSU. We did not experience any problems with this configuration and never once had the low power dialog box pop up. We did remove the second Molex connector and tried running the card on just the primary power plug. As soon as the computer booted into Windows the low power dialog box popped up informing us we were running in a reduced power mode.