NVIDIA GeForce 6800 GS
As mentioned previously, GeForce 6800 GS is powered by NV42. A PCI Express part, NV42 uses 5 NV4x-class (obviously, but it’s worth pointing out) vertex units to generate geometry for a triplet for fragment quad processor groups (what you’d otherwise call 12 pixel shaders), which output into eight ROP units, those bits of silicon responsible for drawing the finished pixels to your screen after prior processing.It’s nothing we haven’t seen before in terms of capabilities and unit counts, and indeed NV42 is the basis of already available GeForce 6800 Go products, but it’s nothing we’ve seen before in terms of clocks. Hitting the 425MHz mark on the GPU core, shader and texture rates are competitive with GeForce 6800 GT (a 6/16/16 GPU clocked at 350MHz). Indeed, vertex processing rate is higher on the GS than the GT!
Only pixel output rate is much less, due to the lessened count of ROPs, but then NVIDIA have recently been Kings of that particular balancing act, judging well the silicon budget they need for drawing finished pixels.
The theory is that if you don’t have a peak output of pixels to draw, per clock, coming out of your pixel units, don’t waste silicon providing the large units to do so. G70 makes do with 24 pixel units into 16 ROPs. NV43 makes do with 8 pixel units into just 4 ROPs. So while GeForce 6800 GT has prodigious theoretical pixel output rates, the reality is that the ROP count was largely too much.
Paired with the same 500MHz memory (256MiB in total on a 256-bit bus) as found on the first 6800 GT, it’s competitive with the SKU it replaces in that sense. So don’t think badly of GeForce 6800 GS because of a ROP deficiency. As we’ll show you shortly, it easily keeps up in modern games.
And that’s pretty much it, in a nutshell. NV42 contains all the Shader Model 3.0 and SLI goodness that we’ve talked about dozens of times on HEXUS.core, since NV40 showed up in April 2004 (technically SLI came with PCI Express, but you know what we mean). That means you can pair up GeForce 6800 GS boards for more performance if you wish, and it’ll run all the latest games.
Worth a closer look, then, especially since it’s close to £150 a throw? Yeah, we think so too. The reference board has been knocking around HEXUS for a while now, so it’s about time we showed you it in more detail.
