Given the introduction you probably won't be surprised to hear that indeed the 9800 GTX is just another confused result of nVidia's recent numbering system because under its bonnet this card is essentially just an overclocked 8800 GTS 512, sporting as it does, the same 128 stream processors, 512MB of memory, 256-bit memory interface, texture addressing and sampling stats, and video processing capabilities. It is the 8800 GTS 512 OC (Overclocked Edition) in all but name.
In fact, with a core clock speed of 675MHz, a 1,688MHz shader clock and memory running at 1,100MHz (effectively 2,200MHz), the overall pixel fillrate is actually lower than the 8800 GTX, resulting in lower performance at high resolutions or when anti-aliasing is enabled. Also, there's less memory and less memory bandwidth so again, higher resolutions and anti-aliasing levels will really tax this card. It does have a greater overall shader throughput, as a result of the faster shader clock, so with more and more games putting more demand on shaders this should keep it ahead when at the highest in-game detail settings. However, it's only a small increase and considering how long the 8800 GTX has been around we would normally expect a larger leap. In the end, we can't help but feel a little disappointed with the likely performance of the 9800 GTX.
That said, there are a few new features that have been brought to the table. The first is support for three-card SLI, or tri-SLI, a feature that has previously only been available with the 8800 GTX and 8800 Ultra. There's also support for HybridPower, which lets you switch between using the low power onboard graphics of a motherboard, for when you're not gaming, and a power hungry discrete graphics card for when you need the 3D processing power. This feature is only available with certain nVidia compatible chipsets, namely the 790a, a sample of which Leo recently reviewed, along with an as-yet unnamed chipset that will support Intel CPUs.
So, on balance, there's plenty going for this card in terms of internal features so it's good to see it's the same story when you look at the physical features of the card as well. At 270 x 37 x 100mm it is longer than your average ATX motherboard and takes up the width of two normal expansion cards. However, this is par for the course for a graphics card of this power.
The cooler is much the same design as that used on the original 8800 GTX with a large single fan sucking air in from the front of the card, blowing it across an array of heatsinks and heatpipes, and out the back through a grilled section that aligns with the second expansion card slot on your case. Also like the 8800 GTX, it is whisper quiet when the card is idling and although it gets noisier during gameplay it is a low whoosh rather than a high pitched squeal or buzz. Similarly, while the card did get understandably hot, the exhausting nature of the cooler means it shouldn't require too much additional airflow in your case.