NVIDIA GeForce 7800 GT: Rounding Out The High End
by Derek Wilson & Josh Venning on August 11, 2005 12:15 PM EST- Posted in
- GPUs
The Card, Specs and Test
The 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.
| Card Comparison | |||
| 6800 Ultra | 7800 GT | 7800 GTX | |
| Vertex Pipes | 6 | 7 | 8 |
| Pixel Pipes | 16 | 20 | 24 |
| ROP Pipes | 16 | 16 | 16 |
| Core Clock | 425 | 400 | 430 |
| Mem Clock | 550 | 500 | 600 |
| MSRP | $399 | $449 | $599 |
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.
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Hacp - Thursday, August 11, 2005 - link
THANK YOU FOR MAKING ALL THE POSTS VISABLE! IT WAS ANNOYING CLICKING ON THE DOWN BUTTON!sry for the caps :).
crimson117 - Thursday, August 11, 2005 - link
Page 4, first two sentences:"One of the most demanding games we test in terms of graphics, Doom 3 shows some impressive gains here. First lets compare the 6800 Ultra and the 7800 GT."
should be
"One of the most demanding games we test in terms of graphics, Doom 3, shows some impressive gains here. First let's compare the 6800 Ultra and the 7800 GT."
note: the comma after Doom 3 makes "One" the subject of the sentence. Alternatively, it could be:
"Doom 3 is one of the most demanding games we test in terms of graphics, and it shows some impressive gains here."
pio!pio! - Thursday, August 11, 2005 - link
Can the sample card you obtained be overclocked to anywhere near GTX speed? (cpu and memory)Also I know it's early, but any thoughts on softmodding it to enable more pipelines?
JNo - Thursday, August 11, 2005 - link
Good question. xbitlabs.com state in their review that, "The GeForce 7800 GT reference graphics card we had in our lab proved quite overclockable. We managed to increase its working frequencies from 400MHz for the chip and 1000MHz for the memory to 470MHz for the chip and 1200MHz for the memory, which should ensure a significant performance increase during our tests." Unfortunately they did not include overclocked results in their graphs.Also, xbitlabs noted that the PCB is shorter than for the GTX, that the cooler is shorter and also commented on noise levels, given that unlike the GTX, the GT is apparently unable to regulate its fan speed. It is a shame that anandtech missed out on such details.
mmp121 - Thursday, August 11, 2005 - link
I'm thinking this is a typo when you re-made the charts for BF2 to include the NV 6800 Ultra. The ATI Radeon X800 XT is really the ATI Radeon X850 XT PE right? Maybe I am wrong. Just wanted to point out the fluke so you guys can fix it. Good read so far!DerekWilson - Friday, August 12, 2005 - link
The BF2 numbers use the X800 not the X850Phantronius - Thursday, August 11, 2005 - link
Waaaah!!! Why no 6800GT comparison and why the hell didn't you guys benchmark Far Cry with HDR Mode???????AtaStrumf - Thursday, August 11, 2005 - link
I really resent this comment on page 1:"Until performance is increased beyond the 7800 GTX, it will be hard for us to see a reason for a new desktop 7 series part."
So you rich boys got your flashy new toys and now you see no need for a new desktop 7 part, because you're too busy thinking about how you're gonna be playing games on the go (i.e. your new laptop GPU).
What about us stuck at 6600 GT level. Don't we deserve an upgrade??? Like a 12-16 pipe/ 256-bit 7600 GT? I guess that we are just fine, since we're stuck with 1280x1024 res monitors anyway, right? WRONG! We've been cheated out of a significant upgrade long enough. Until 6600 GT there was only BS in the mainstream for about 2,5 years (R9500/9600/PRO/XT/GF5600/Ultra,...) and we're not going back there, no sir!
Same sh!t when people with broadband post large uncompressed images on the web and forget about all those with dial-up, even though they themselves left that sorry bunch not too long ago. The world is weee bit bigger than your own back yard and someone writing for a site as big as AT should really know that.
DerekWilson - Friday, August 12, 2005 - link
I just want to add my two cents as well ...I will agree with you that the 6600 GT was the first real solid mainstream option in a while. It's a good card.
I'll argue that the next mainstream card you'll want to look at is the 6800 GT. There are 128MB parts and 256MB parts all with 256-bit busses and 16 pixel pipes at good clock speeds.
As other's have said, releasing a G70 part with the same specs as the 6800 GT will have the same performance as well.
We tried to explain in the article that the 6 Series comprises the rest of the lineup going forward. There are no performance gaps that the G70 needs to fill in. The only reason NVIDIA would want to release slower G70 parts would be to phase out the 6 Series part at that same speed grade.
It also doesn't make sense for NVIDIA to immediately release a slower G70 part. The lower transistor count and more mature process used on NV4x chips will likely make it easier for NVIDIA to sell the parts at a lower price and higher profit than equivalently performing G70 parts. The economics of this are very complicated and depend quite a bit on NVIDIA and TSMC and the cost per IC for NV4x and G70 chips.
It would almost make sense for NVIDIA to take less functional G70 chips and sell them as 6 Series parts. But maybe I'm wrong. Perhaps NVIDIA will think it can trick people into thinking a part with the same performance as a 6800 or 6800 GT and a 7 Series name is worth more money.
It really shouldn't matter to anyone whether 6 Series parts keep falling in price or other 7 Series parts come out. I stand behind my statement. We'll see lower performing G70 parts come out if and when it becomes more financially viable for NVIDIA to sell those parts than NV4x parts. There really isn't any other factor that matters.
Transparency AA may be an interesting thing, but moving towards the budget end of the spectrum will tend to make the performance impact of Transparency AA too high to matter. Other little tweaks and features have already been covered and aren't that compelling over the 6 Series, and seeing a G70 perform the same as an NV4x for the same price really wouldn't be that exciting no matter what my budget looks like.
Derek Wilson
coldpower27 - Thursday, August 11, 2005 - link
It would be interesting to see if the 90nm based 7600 part has a 256Bit Memory Interface, as it seems 256Bit Memory Interface cards usually have a minimum die size of around 200mm2 just out of range of a high volume mianstream level card.I would certainly want a 7600 GT if it had a similar pipeline configuration in comparison to the 6800 or 6800 GT because G7x does have some improvements I like, most notable the improvement in HDR performance levels, and Transparency AA, also what about WGF 1.0 support? It usually for the most part better to have a new mainstream card based on newer tech then just shifting older technology into the lower price points, as those cards aren't meant for those price points and are usually more expensive to produce.
Not all of us can even afford the current 399US price point of 7800 GT.