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Asus V9950 Ultra - Under the skin
Probably the most intriguing aspect of the Geforce FX 5900 is public perception. They say reputations take years to build, but only a few minutes to destroy and if that were the case then NVIDIA would have nothing apart from a name and logo after the NV30. What is interesting to see from our point of view is how the public felt about this card before and after it was released. After presenting what can be only described as a lacklustre product in the form of the FX 5800 earlier this year, the 5900 had some bridges to build. Isambard Kingdom Brunel, the most prolific bridge builder ever would have had trouble in bridging the gap NVIDIA had created with the community thanks to sacrificing both speed and image quality in the FX 5800. So has NVIDIA bridged that gap with the FX 5900 Ultra? The raw materials are there and the NV35 is no Tacoma Narrows Bridge, but it will take more than one product to rebuild their reputation after such a poor product.

It's no secret that frames per second, the old unit of measure in graphics card performance is starting to take the long walk off into the yonder that is historical computer references with both of the big players, ATI and NVIDIA admitting that today image quality is certainly as important if not more so in determining the overall performance of a video card. Image quality is dictated through both design of the GPU and software (principally drivers). Some of the image quality issues that were present with the FX 5800 were corrected through driver updates, but the fact still remained that the GPU itself was heavily underpowered. The NV35 that powers the FX 5900 and FX 5900 Ultra solves the horsepower problem quite satisfactorily. Image quality as we'll find out is also a lot better and can provide the ATI's Radeon 9800 with a good fight.

We've already looked at several retail Geforce FX 5900 cards and today we look at one of the first retail Geforce FX 5900 Ultra cards to hit the shelves here in the United Kingdom, and you'll be happy to hear it doesn't feature the reference 2 slot heatsink. The Asus V9950 Ultra is one of the more interesting FX 5900 Ultra boards on the market thanks to a number of changes (albeit superficial) the Taiwanese giant has made.

The V9950 Ultra has much of the same features we saw in the V9950 a few weeks ago, except for a couple of key points. Being of the 'Ultra' flavouring we see the NV35 GPU run a little faster (850MHz, 50MHz more than the 'non Ultra'), 256MB of DDR SDRAM (as opposed to 128MB) and it too runs a little faster (850MHz DDR, 50MHz faster than a 'non Ultra'). So whilst technologically there might not be any difference in the GPU itself, other than the frequency it's running at, due to the higher frequency at which the memory is operating at, we get extra bandwidth between the GPU and the memory. Since it's a perennial question, the question of how memory bandwidth is calculated, we'll use the FX 5900 Ultra as an example :

Total memory bandwidth = memory bus width * memory frequency (always take the SDR memory rate) * 2 (only if it's DDR memory)

In the case of the FX 5900 Ultra we have :

27.2 GigaBytes/sec = 256bit bus width * 425MHz * 2

You might have heard that one of the reasons that our old doorstop, the FX 5800 Ultra performed so poorly was due to a lack of memory bandwidth. Although it was using the newer DDR II modules, it still had a 128bit memory bus which meant that one of the key components in that equation above was compromised. To compensate, NVIDIA had to run the memory at very high frequencies. This resulted in the requirement of the FX Flow cooling system and all the noise that went along with it. Putting the figures into the equation for the FX 5800 Ultra we have :

16 GigaBytes/sec = 128bit bus width * 500MHz * 2

Add lacklustre memory bandwidth to the latency issues that are still present in DDR-II (even with ATI's Radeon 9800 256MB unit which utilizes DDR-II memory) and you have a relatively poor memory subsystem. So whilst you may think that NVIDIA have taken a step back with the FX 5900 by using DDR-I memory it's clear that from the increase in memory bandwidth and even though DDR-I may not sound as exotic as having DDR-II on board, the raw performance figures justify its inclusion.

If you want a more detailed read on buses we recommend you read this article.

We also mentioned latency. A number of you have asked what latency is so we'll try and explain it in a little detail here. The definition of latency is :
The time taken between the start of a message's transmission from it's source to the beginning of the receipt at the receiver.
So think of the source being the RAM that is present on the video card and the receiver being the GPU itself. If there is a large delay between the data leaving the RAM and 'entering' the GPU then that will undoubtedly decrease performance.

Click to enlarge

We've already talked in detail about the NV35, so here is a quick recap. For fuller descriptions we recommend you read our MSI FX 5900 and FX 5900 roundup articles.
  • CineFX 2.0 - the engine behind the processor, it brings 128 bit colour, two levels of pixel precision (16 and 32 bit), increases the number of instructions for vertex processing (up from 128 to 65,536), more vector registers (16, up from 12), new pixel shading instruction set and dynamic branching and looping.
  • UltraShadow - speeds up the processing of shadow volumes by "eliminating unnecessary areas". A technology that will have greater importance when games like Doom 3 appear. The exclusion of areas will make some people cry foul, however the less pedantic amongst you will not mind what goes on out of your view, just as long as image quality doesn't suffer.
  • 256 bit memory bus - We've already talked about this in great detail, nonetheless an important "upgrade" to the overall bandwidth present.
  • Intellisample HCT - an evolution of the original Intellisample technology we first saw on the NV30 core. Improved compression allows more data to be transferred on the memory bus in less time.
  • So that aside lets take a look at the Asus V9950 Ultra.