NVIDIA's Tiny 90nm G71 and G73: GeForce 7900 and 7600 Debut
by Derek Wilson on March 9, 2006 10:00 AM EST- Posted in
- GPUs
Quad SLI and Purevideo
Today NVIDIA is also putting its Quad SLI initiative into action. Unfortunately, it doesn't look like they will be selling add-in Quad SLI based cards in the near future, but for those in need of such a setup will be able to find them from various system builders. Obviously this is a little at odds with the enthusiast community who prefer to build their extreme rigs themselves, but NVIDIA cites thermal, space, and power concerns not easily addressable by the individual as a reason for pushing out this hardware to system builders first. How many power supplies out there can provide enough power for SLI and CrossFire, let alone have the headroom to support four GPUs? Similarly, thermal issues could definitely be a problem in a case without good air flow.
NVIDIA would not commit to any timeframe for bringing Quad SLI to the add-in market, but they did indicate that they want the requirements for Quad SLI to be clear and readily obtainable by an individual. The landscape does have to be ready for something like this. Even if an enthusiast could put together a thermal solution to support Quad SLI, most of us don't dabble in power supply design and manufacture on the side. Unfortunately, we don't have any Quad SLI cards to test out either, but we are certainly looking into getting our hands on a system. We will have benchmarks as soon as we are able.
Quad SLI will provide a few new modes that are basically extensions of what the current SLI technology offers. Split frame rendering (SFR) will now split the frame 4 ways, and alternate frame rendering (AFR) will support one GPU rendering every 4th frame. The latter mode will provide the most benefit in games that support it as geometry processing will be well divided among the GPUs. Additionally, AFR of SFR will take each frame and split it among a pair of GPUs. Each pair then renders every other frame. This mode will be compatible with all titles that currently support AFR. Additional SLI AA modes will also be added to take advantage of up to 32x AA.
The Quad SLI is setup using what NVIDIA calls an x48 PCIe interconnect. This takes the x16 connection from the motherboard and both video cards and manages all 3 at full speed. In this way, full use can be made of available PCI Express bandwidth, both to and from the system and between GPUs.
Last week NVIDIA also launched an update to their Purevideo driver which is supposed to deliver increased performance and support, specifically for H.264 video playback. We will also be looking into updating our video quality and performance tests with the new Purevideo driver as soon as possible. The biggest change we would like to see from Purevideo is a free download from NVIDIA. Currently requiring users to purchase more software in order to get full functionality of advertised features fomr their hardware is more than a little disappointing.
Today NVIDIA is also putting its Quad SLI initiative into action. Unfortunately, it doesn't look like they will be selling add-in Quad SLI based cards in the near future, but for those in need of such a setup will be able to find them from various system builders. Obviously this is a little at odds with the enthusiast community who prefer to build their extreme rigs themselves, but NVIDIA cites thermal, space, and power concerns not easily addressable by the individual as a reason for pushing out this hardware to system builders first. How many power supplies out there can provide enough power for SLI and CrossFire, let alone have the headroom to support four GPUs? Similarly, thermal issues could definitely be a problem in a case without good air flow.
NVIDIA would not commit to any timeframe for bringing Quad SLI to the add-in market, but they did indicate that they want the requirements for Quad SLI to be clear and readily obtainable by an individual. The landscape does have to be ready for something like this. Even if an enthusiast could put together a thermal solution to support Quad SLI, most of us don't dabble in power supply design and manufacture on the side. Unfortunately, we don't have any Quad SLI cards to test out either, but we are certainly looking into getting our hands on a system. We will have benchmarks as soon as we are able.
Quad SLI will provide a few new modes that are basically extensions of what the current SLI technology offers. Split frame rendering (SFR) will now split the frame 4 ways, and alternate frame rendering (AFR) will support one GPU rendering every 4th frame. The latter mode will provide the most benefit in games that support it as geometry processing will be well divided among the GPUs. Additionally, AFR of SFR will take each frame and split it among a pair of GPUs. Each pair then renders every other frame. This mode will be compatible with all titles that currently support AFR. Additional SLI AA modes will also be added to take advantage of up to 32x AA.
The Quad SLI is setup using what NVIDIA calls an x48 PCIe interconnect. This takes the x16 connection from the motherboard and both video cards and manages all 3 at full speed. In this way, full use can be made of available PCI Express bandwidth, both to and from the system and between GPUs.
Last week NVIDIA also launched an update to their Purevideo driver which is supposed to deliver increased performance and support, specifically for H.264 video playback. We will also be looking into updating our video quality and performance tests with the new Purevideo driver as soon as possible. The biggest change we would like to see from Purevideo is a free download from NVIDIA. Currently requiring users to purchase more software in order to get full functionality of advertised features fomr their hardware is more than a little disappointing.
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yacoub - Friday, March 10, 2006 - link
Any idea when we'll see a comparo showing the 7900GT against following cards?X800XL
X1800XL
X1800XT
7800GT
It is important for people running cards like those right now to know how much gain they will see going with a 7900GT versus going with a 7900GTX. Clearly they can see the difference between the 7900GT and 7900GTX on this review, but no one knows what improvement the 7900GT would have today (with today's drivers and games) over the cards many people are still using such as the X800XL or 7800GT.
It's important to know if the 7900GT offers enough gain for such users over their current cards, or whether they should step all the way up to the 7900GTX.
Thanks.
spinportal - Friday, March 10, 2006 - link
I definite like the review and the presentation Derek. There are definite tradeoffs for price, power load and performance.All this talk of HDCP, DX10 (with Vista) and HD (1080p) PureVideo vs. AVIVO (shame on you nVidia for asking more from the consumer when ATI bundles such goodies) just around the corner, I'm still on the wait-n-see list before making the plunge to PCIe (besides AMD's M2 chipset, and Intel's DuoCore refresh to spank the PentiumD).
What I don't get is how drastic ATI's ability to do AA with HDR (how many games truly support this? FarCry? but Splinter Cell can't? Half-Life2 engine?) shines above nVidia's lack. Is this the only feature ATI has an exclusive win over nVidia?
Also, there was a preface of the 7900GT being marginally faster than the 7800 GTX-256, with a nice price advantage going to the 7900GT (as well as lower power load), killing off the 7800 line for newcomers. So where is ATI's high-mid or low-high 300$ competing part? Along with the 1900XTX being a gratutitous weak "ultra" offering, since a Crossfire only paces the 1900XT, "wasting" the XTX's 5% extra power, except to prove the King-of-the-Hill mentality. More power to ATI's customers paying a cost premium.
The 7900GT SLI might be penny-wise & pound-foolish, as two of these cards cost substaintially more (350x2 vs. 550 = ~150$ / 20%) a single 7900GTX, draw more power (hence hidden cost of a beefier UPS upgrade) for roughly ~15% gain (YMMV with oc'ing, or manufacturer tweaks).
And sure, the ATI X1800GTO squeaks a victory from the nV 7600GT, with est. end of March '06 MSRP of 249 vs. ~180-200. For the non-graphic fanatic, cost-conscious WoW player, the 7600GT is a nice target for newer PCIe. For the gung-ho FPS shooter, for a bit more, why not aim for the 7900GT instead of the X1800GTO?
For curiosity sake, Derek, could you downgrade a 7900GTX to GT core/mem clock speeds and see how much a difference the extra 256MB makes? If the GT has good OC headroom, it can be a better bargain. With the same basic core, how much can the clock be pushed on the GT? As for memory, how much is 256MB more of GDDR3 RAM worth (over the same bus), and how far can the GT's bandwidth get pushed to help the benchmarks? Is nVidia able to push a GT to a GTX due to better active cooling? This might be wait tweakers looks for to justify their purchase. We see that a 7800GTX-512 had definitive victories over a 7800GTX-256/7900GT of about ~20%, which does bring nearly playable frame-rates into the 60 fps point. Maybe an enterprising third-party might offer a $400 7900GT-512 with a slightly higher mem clk; there is room for opportunistic pricing there.
yacoub - Friday, March 10, 2006 - link
I like what XFX and eVGA are offering: http://www.firingsquad.com/hardware/nvidia_geforce...">http://www.firingsquad.com/hardware/nvi...orce_790...yacoub - Friday, March 10, 2006 - link
Good article, good conclusion.7900GTX @ $475 is perfect competition for the X1900XT/XTX.
7900GT @ $300 is a great price for 7800GTX performance.
A 7900GT with a quieter, better cooling solution and accompanying overclock for around ~$350 will be my next purchase as soon as Asus or Gigabyte or someone releases such a card at such a price.
Leper Messiah - Friday, March 10, 2006 - link
too bad the only 7900GTX I've seen is $559.00 Man, I though I read somewhere in Video that these things were supposed to be uber cheap. Guess that was just rumor. :(yacoub - Friday, March 10, 2006 - link
Really? I saw ones as low as $499 in the RealTime Pricing results..KHysiek - Friday, March 10, 2006 - link
I know it can be used to beat world record of fastest graphics cards, but for whom this tests are targeted. I think they are useless for 99.99999% of readers. Atlhon FXs, SLIs all over the place and almost none nonSLIsetups of currently available cards. How typical user, which has card 6-18 months old is supposed to evaluate speed of new cards and value of upgrading. I think it's the main task of such test - convince people to upgrade. Who have such systems like your testbed and who use SLI in real life - 0.00001% of these readers. Maybe even less.yacoub - Friday, March 10, 2006 - link
some of us have been making this request for months now but it routinely falls on deaf ears. it appears most anandtech readers would prefer to read what is essentially technical advertising for GPU performance as tested in ubersystems 99% of us will never own.Egglick - Friday, March 10, 2006 - link
Trying to compare cards with all those SLI and Crossfire scores everywhere can get really irritating.bigboxes - Thursday, March 9, 2006 - link
Can we please have separate charts for SLI/Crossfire setups and single cards that normal people will end up using. That way we can easily compare apples to apples. I'm sure that the 1% of you that use an SLI/Crossfire setup will like the articles, but the rest of us normal people will appreciate a direct comparison between the various single cards.