NVIDIA GeForce 8800 GTS 512 & GeForce 8800 GT 256MB: Playing with Memory and G92

Generally, you don't see many products released in December. It's getting a little too late to make dramatic impacts on Q4 earnings as many have already done their holiday shopping. If a company is going to release a new product this late in the year, there's generally a good reason for it, or it's simply a product we'll never see.

At the end of October NVIDIA introduced its GeForce 8800 GT, based on a brand new 65nm GPU codenamed G92. The 8800 GT quickly outclassed virtually every NVIDIA GPU, making most of the G80 lineup obsolete by offering better performance at lower prices. A higher end incarnation of the 8800 GT's G92 was inevitable, we just didn't expect to see it this soon.

The GPU is the same, we're still looking at a G92 derivative part, but the card is all new: the GeForce 8800 GTS 512.

A dual-slot G92, the larger heatsink keeps this card a bit cooler than the 8800 GT but with no increase in sound

While NVIDIA is in a better position than AMD is these days, NV marketing could stand to learn from AMD's recent changes. The Radeon HD 3800 series carry no tacky suffixes, just four digit model numbers to keep things nice and simple. Not only is the GeForce 8800 GTS 512 absurdly long, it also further complicates the 8800 product line. If you'll remember back to our 8800 GT review, the 8800 GT is faster than the old G80 based 8800 GTS. The new 8800 GTS 512 is faster than the 8800 GT, and thus faster than both the 320MB and 640MB versions of the old GTS. So you end up with the following lineup today:

8800 Ultra > 8800 GTS 512 > 8800 GTX > 8800 GT > 8800 GTS 640 > 8800 GTS 320

Confusing to say the least, but if you can forget about all of the other products on the market you'll see that there are only two NVIDIA cards to be concerned with: the 8800 GTS 512 and the 8800 GT.

Architecturally, the 8800 GTS 512 adds another group of 16 shader processors over the 8800 GT. We'd suspect that the 8800 GT has the same number of SPs, but with one block of 16 disabled to increase yields.

Since it's based on G92 we get a 1:1 ratio between texture address and texture filtering, giving the GTS 512 the first leg up over the much more expensive 8800 Ultra. With a 650MHz core clock and 1.625GHz shader clock, the GTS 512 has an 8% shader processing advantage over the Ultra.

The only area where the 8800 GTS 512 loses to the 8800 Ultra is in its total memory bandwidth. The 8800 Ultra, like the 8800 GTX, features a 384-bit wide memory bus while the GTS 512 uses the same 256-bit memory interface from the 8800 GT. There are definite cost advantages to going with a 256-bit memory bus; NVIDIA can build a smaller chip with fewer pins, and make up for the loss in memory bandwidth by shipping the card with faster memory devices. Despite the 1.94GHz memory data rate on the 8800 GTS 512, the 8800 Ultra and GTX have around a 40% memory bandwidth advantage, resulting in better performance in memory bandwidth limited scenarios and high resolution AA tests.

Despite being built on a 754M transistor die, the move to 65nm has made G92 much smaller and thus cheaper to make than G80, which is why we're seeing NVIDIA eagerly replacing its 8800 lineup with G92 variants.

Pricing and Availability

With the disappointing aftermath of the 8800 GT launch, we're better prepared to analyze expectations for what will happen with the 8800 GTS 512. Keep in mind that the 512MB 8800 GT is supposed to be a $250 part, but in reality it's selling for around $300 in the US. The GTS 512 is expected to sell for $299 - $349, but we're already hearing from manufacturers that prices will be much higher.

The XFX GeForce 8800 GTS 512 at reference clocks will carry an MSRP of $349, and the overclocked XXX edition will sell for $379. The GTS 512 could possibly sell at $349, but we wouldn't be too surprised to see it priced even higher in the market given its close proximity to the 8800 GT.