Meet the 7900s
NVIDIA has given the G71 a pair of initial assignments. The flashiest of the two is in the GeForce 7900 GTX, its new top-of-the-line video card. On the 7900 GTX, the bulk of the G71 GPU will flip bits at 650MHz, while the vertex processors will be clocked a few ticks higher at 700MHz. (Yes, like the G70, the G71 has multiple internal clock domains.) The GPU will share a card with 512MB of GDDR3 memory running at 800MHz, or effectively 1.6GHz in the highly caffeinated world of DDR memory chips. NVIDIA estimates that this combo will require about 120W worth of cooling capacity.
Cosmetically, the GeForce 7900 GTX is a dead-ringer for its little brother, the GeForce 7800 GTX 512, adorned with the same dual-slot cooler with wicked heatpipe fingers extending into its fins. Thanks to an additional hundred megahertz of core clock speed and just a tick less total memory bandwidth, though, the 7900 GTX should generally get the better part of any sibling rivalry. Of course, such bragging rights rarely come cheap, and their actual price tag can fluctuate wildly depending on the situation. Perhaps that's why NVIDIA quotes a price range of between $499 and $649 for the 7900 GTX. I suppose they're also hedging their bets after ordering up too few copies of the GeForce 7800 GTX 512 and watching prices shoot into the ionosphere. The hope is, they say, for this new GTX's street prices to fall much closer to the $499 part of that range than the $649 one. We've done some digging, and I believe 7900 GTX card should start at $499 and range up to $599, with "overclocked in the box" clock speeds as high as 700MHz core and 900MHz memory.
There's nothing like playing some F.E.A.R. on a pair of GeForce 7900 GTXs after a long weekend of yachting, but most of us will probably be more personally interested in the G71's other assignment, the GeForce 7900 GT. This puppy spins its core clock at 450MHz, with the vertex shaders at 470MHz. This more modest GPU config stores its pixels in 256MB of GGDR3 memory clocked at 660MHz. That 200MHz drop-off in core clock speed from the GTX to the GT is precipitous, and thus NVIDIA has deemed it unnecessary to deactivate any of the G71's functional units for the sake of product segmentation; the 7900 GT keeps all of the G71's 24 pixel shaders, eight vertex shaders, and 16 ROPs intact.
Look at that itty bitty cooler! Now that's just showing off. The 7900 GT's thermal design power is only 80 watts, so NVIDIA stuck a cooler smaller than a deck of cards on its reference design and called it a day. With a better cooler, the 7900 GT could have some serious overclocking headroom.
In fact, more than one of NVIDIA's board partners will offer multiple versions of the 7900 GT, with some versions having better coolers strapped to the side, higher clock speeds, and higher prices. Perhaps that's why NVIDIA told us the 7900 GT's expected price range is between $249 and $399. You've gotta use FP16 to get that kind of dynamic range (har hargraphics geek humor.) Based on what we've heard from folks in the know, I would not expect to see 7900 GTs selling for much under $299 right out of the gates. Instead, I'd look for 7900 GT cards to begin life between $299 and $349 at online stores, with "overclocked in the box" variants selling in the higher part of that range. The more expensive 7900 GTs will boast core clock speeds as high as 560MHz and memory clocks as high as 625MHz. If I'm wrong about that, we'll find out soon, because both the 7900 GT and GTX are slated to be available today at online vendors.