|  Physically, the GeForce 6800 Ultra looks much like the GeForce 5950 Ultra, but don't let initial impressions fool you. The GeForce 6800 Ultra incorporates some cutting-edge technology, and has quite a few new and useful features. If it's not entirely clear in these photos, the GeForce 6800 Ultra's cooling solution is still a two-slot design; the model we have here does encroach on the first PCI slot. The blower and shroud are designed to pull air in through the front, and blow it across the heatsinks mounted over the GPU and RAM. When operating at full speed, we found the fan to be somewhat louder than the ones installed on most of the retail-ready 5950 Ultras we have reviewed, but we expect NVIDIA's AIC partners will come up with some innovative cooling solutions of their own design. We wouldn't be surprised if a few single-slot, near silent models hit store shelves in the coming months. Also notice that our sample was equipped with two DVI connectors, for those looking to run dual-independent digital displays (or dual analog displays using DVI-to-DB15 adapters). Dual-DVI cards have been few and far between, but we're told that not all 6800 Ultras will be dual-DVI, so don't get too excited just yet. Some will ship with one DB15 and one DVI connector. The next aspect of the GeForce 6800 Ultra that may catch your eye are its dual Molex power connectors. This NV40 core is built using a .13 micron manufacturing process, and is comprised of roughly 222 million transistors. If you're keeping track, that's approximately 25% more transistors than a P4 Extreme Edition CPU, which makes the NV40 an extremely complex (and large) ASIC. As such, it demands a lot of power. NVIDIA is recommending 480W power supplies be used with the GeForce 6800 Ultra. When connecting the power cables, they can't be split from a single connection either. The GeForce 6800 Ultra requires connections from two supplemental power rails. Keep this in mind if you think a GeForce 6800 Ultra is in your future, as a power supply upgrade may be in order as well. The need for this kind of "external" power stems from a limitation within the AGP spec. AGP slots can provide a maximum of only 25W of power to the video card. PCI Express should help alleviate the situation a bit, as the PCI Express standard calls for 60W. |
| We also disassembled the cooling hardware mounted on our GeForce 6800 Ultra, to get a closer look at the underlying PCB, memory and the NV40 chip itself. Once we had the card apart, It was interesting to find that the heatsinks used on the card were constructed of aluminum, instead of copper. During conversations with NVIDIA, we were told that although the NV40's die is larger and requires a lot of power, it runs cooler than NV38 because of tweaks made to the manufacturing process and its slightly lower clock speed. | We haven't done extensive testing, but our experience with the card so far seems to back up this claim. At idle we witnessed core temperatures hovering around 36C. After a few hours of benchmarking though, we saw temperatures climb into the upper 40s, but we did not monitor temperatures during peak activity due to time constraints. With more elaborate (and expensive) copper coolers, however, temperatures could be brought down even lower. It was also interesting to find that all 256MB (8x32MB) of the RAM installed on the card, was mounted to one side of the PCB. Samsung's GDDR3 chips are available in higher densities than standard DDR RAM, which eliminates the need to mount chips on the backside of the card, unless NVIDIA plans to increase the RAM over 256MB. Right in the center of the PCB you'll see the massive NV40 itself. The die is so large because NVIDIA has designed the NV40 to have far more pixel shading performance than last generation's high-end parts. The NV38 (GeForce FX 5950 Ultra), for example, is a 4x2 or 8x0 (Z-only, no color data) architecture. In most real-world gaming scenarios, this means it can process 4, dual textured pixels per clock cycle which equates to a theoretical peak fillrate of 3.8GTexels/s. The NV40, on the other hand, is a 16x1 or 32x0 architecture. The NV40 has four times the number of pixel pipelines as the NV38, which accounts for a large number of the transistors that comprise the core. NVIDIA didn't only increase the number of pipelines, but they have also incorporated a second pixel shader unit per pipe and have brought the number of vertex units up to 6 as well. Although we'll be shining the spotlight on the GeForce 6800 Ultra today, NVIDIA is also announcing the 6000 "non-Ultra". The GeForce 6800 is based on the same NV40 architecture, but it will have "only" 12 pixel pipelines, as opposed to Ultra's 16. NVIDIA hasn't disclosed final clock speeds just yet, but they have informed us that the base GeForce 6800 will be a single-slot design (like the card pictured at the very top of this page), and it will require only one Molex power connection. As more solid information about the GeForce 6800 comes in, we're sure we'll be able to tell you more, but for now, lets move on to some of the GeForce 6800 Ultra's other key features... |
