NVIDIA GeForce 7800 GT: Rounding Out The High Endby Derek Wilson & Josh Venning on August 11, 2005 12:15 PM EST
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The Card, Specs and TestThe basic setup of the GeForce 7800 GT is the same as the GTX. We still have one single and one dual-link DVI port and a 6-pin power connector on a x16 PCI Express card. The stock HSF solution is the same, and the silicon hasn't changed either. The GT is still based on the G70 with a few blocks disabled.
The G70 on the 7800 GT features 7 vertex pipelines, 20 pixel pipelines and lower clock speeds (400/500 core/mem) than the GTX. This still ends up putting the 7800 GT above the 6800 Ultra in terms of vertex and pixel performance even though it lags in core and mem speed. Here's a quick table of the differences between the current high end NVIDIA parts.
|6800 Ultra||7800 GT||7800 GTX|
The 7800 GT comes in the lowest on clock speed and memory bandwidth, but the combination of pipelines and clock speed give the 7 series GT a definite theoretical advantage over the 6800 Ultra in the vertex and pixel processing department. Obviously, the GTX has all the rest beat, but the real question is: how much real world difference will it make? We've already seen that the 7800 GTX performs very well compared to the 6800 Ultra, and, ideally, we would like to see the GT split the numbers. That would leave all three cards with viable performance characteristics.
Price is a very important matter in viability as well, and it is very difficult to tell where the chips will fall. As we can already see with the 7800 GTX, a six hundred dollar suggested price has resulted in street prices mostly between five hundred and five hundred fifty dollars. We don't expect the price of the GT to fall one hundred dollars as quickly as the GTX, but the prices that we see on our Real Time Price Engine show GT products available starting around $400.
Even though NVIDIA haven't recently adjusted their suggested price on 6800 Ultra cards, if the prices don't fall, there will really be no reason to buy a 6800 Ultra (unless it's desperately needed for an SLI update). The suggested retail prices on the 6800 GT and vanilla 6800 have been changed to $299 and $199 respectively. The new pricing layout does give the 6800 Ultra some ability to move down in price a little, if the 7800 GT outperforms it as we expect. It is also possible that the similarity in the price between the 6800 Ultra and the 7800 GT could mean that the 6800 Ultra is being phased out.
Aside from the rather less than spectacular differences between the GT and GTX, we still need to learn about performance. Potentially, this card could be a good buy depending on the numbers that we see. If performance is near that of the GTX, we could save money and still have a very powerful card. If we see numbers near the 6800 Ultra, then we are likely looking at a simple replacement for the 6800 Ultra in NVIDIA's lineup.
The test setup that we used for these performance numbers is the same as the one used in the last few graphics performance articles that we've done:
MSI K8N Neo4 Platinum/SLI motherboard
AMD Athlon 64 FX-55 Processor
1 GB OCZ 2:2:2:6 DDR400 RAM
Seagate 7200.7 120 GB Hard Drive
OCZ 600 W PowerStream Power Supply
We used the NVIDIA 77.77 ForceWare beta driver running on Windows XP SP2.