Fresh from NVIDIA - 7900GT and 7900GTX
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NVIDIA 7900GT - Exterior |
We are not dwelling on the details of the new video processor installed on 7900GT video cards. That is because on 7900GT there is the same G71 as it is on the flagship 7900GTX. In contrast to the 7800GT/GTX couple, this time NVIDIA decided not to cut down the functionality through reducing the number of pipelines. Perhaps, either the new 90-nm process technology proved so good that there is almost no scrap, or the prime cost of new chips is so low that there is no need to "optimize the illiquid asset". Somehow or other - the video processor on 7900GT is absolutely the same as it is on 7900GTX. Anyway, see for yourselves.
 As you can see, the marking differs in only the lack of the letter "U" in the chip name. Interestingly, the chip was manufactured still in January, on the 3rd week of the new year, while the revision being the same - A2. The nominal operating frequency of the chip on 7900GT is 450 MHz, which doesn't make a big difference from the 400 MHz in 7800GT. In view of the fact that on its elder sister the chip runs nominally at 650 MHz, we get an almost 1.5 times as high overclocking potential, of course if the cooling system allows to do that and if there aren't any more serious restrictions like the downstated supply voltage of the video processor. In fact, these two aspects are not a serious obstacle to serious overclockers.
For now, let's look at the exterior of 7900GT and find out what the nominal cooling system can offer.
I think you won't believe me if I say that I was slightly bewildered so see 7900GT for the first time. The major question was just about the very cooling system. Will the unpretentious piece of copper be really able to cope with cooling the chip made up of almost 300 million transistors and running at 450 MHz?
As it turned out, the copper plate with soldered fins (not numerous, by the way) does quite a good job of cooling the GPU. The chip temperature at rest was 42-43 C, and reached 60 C under load. The noise produced by the cooler is almost missing. NVIDIA's new process technology has definitely proved successful.
As regards the PCB, it has been slightly reworked as compared to what we saw on 7800GT. 7900GT has turned somehow shorter. At the same time, the general design and component layout have remained generally intact. Like on the elder sister, a video capture chip is also missing. All the video memory chips not covered with a radiator are positioned on the front side.
The overall memory capacity onboard amounts to 256 MB. Used are chips made by Samsung of 1.429 ns access time, which is equivalent to the nominal frequency 1400 MHz. The nominal operating frequency of memory on 7900GT is 1320 MHz DDR. As you see, that is a bit lower than the nominal. But perhaps it was just the downstatement of the operating frequency plus use of low-voltage memory (1.8 V supply voltage) that allowed to get by without any additional cooling. Use of radiators will let raise the video memory frequency up to 1500 MHz and even higher.
 The reverse side of the card does not bring anything of special interest. There is one point to note, though - it turns out that the positioning of fastening holes for a radiator is the same as that in 7800GT. That suggested the idea - would it be possible to use a standard radiator from 7800GT to cool the GPU and video memory on 7900GT? Therefore, it would be possible to raise the video card's overclocking potential substantially. Unfortunately, a standard radiator from 7800GT wouldn't fit on 7900GT. Because of the shortened PCB design of 7900GT the radiator rested against the DVI connectors. However, the possibility to install a more powerful radiator will most certainly be in demand, and we'll evidently see nonstandard and highly efficient coolers in 7900GT series video cards.
The recommended price for 7900GT has been set to $299, which is nice, although that is the price for the North American region. In Russia, the price will be somehow higher, but we'll find out the difference once the video cards has emerged to the retail.
To get a complete idea of NVIDIA's novelties, we have got to examine their performance. Now on to the benchmarking.
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