Morphing nForce4 Ultra into nForce4 SLI
by Wesley Fink on January 18, 2005 7:30 AM EST- Posted in
- CPUs
Performance: x16 vs. x16/x2 vs. x8/x8 (SLI)
The best way to verify the success of the mod was to run benchmarks. We had already done extensive testing of SLI performance in Anand's NVIDIA's GeForce 6 SLI: Demolishing Performance Barriers. To get right to the point, we tested the Ultra modded to SLI with Half Life 2, Doom 3, and Far Cry at both 1280x1024 and 1600x1200. We also benchmarked at both settings with and without the eye candy - since Anti-Aliasing and Anisotropic Filtering can exact a large hit on a single GPU.We were interested to see exactly what performance you could get with two video cards on the Ultra board before the mod to SLI, so we also ran benchmarks of the performance of x16/X2 Ultra dual-video card mode.
All tests were run on a DFI LANParty UT nF4 Ultra-D and a DFI LANParty nF4 SLI-DR. We first confirmed that test results were the same on the LANParty UT modified to SLI and the LANParty nF4 SLI, which is a native SLI chipset board. There was no difference in performance after the SLI modification to the Ultra chipset, so results are reported as SLI and relevant to either SLI or Ultra modified to SLI.
Video cards were a single MSI 6800 Ultra PCIe or a matched pair of MSI 6800 Ultra in SLI and x16/x2 modes. Memory in all benchmarks was OCZ 3200 Platinum Rev. 2 (Samsung TCCD) at 2-2-2-10 timings. The CPU was an Athlon 64 4000+, and the power supply was an OCZ PowerStream 600.
In the course of testing, we found that we could actually run the x16/x2 mode on either the SLI board or the Ultra board by leaving the jumpers in normal mode, using an SLI bridge across the two video cards, and enabling SLI in the nVidia driver. Results on the SLI board in x16/x2 mode were, as expected, the same on the nF4 Ultra board as shipped or the Ultra after SLI modification. The one huge advantage of the SLI-mod was that once we had SLI-modded the Ultra chip, we could run x16/x2 mode with any nVidia Forceware driver up to 70.xx. The 70.90 driver was the highest driver to support x16/x2 mode even with an SLI chip. x16/x2 would not run, however, with the most recent 71.xx drivers. 71.xx drivers report the board to be SLI-capable, but it does not recognize the second card as an appropriate card for SLI. Clearly, nVidia must have turned off x16/x2 support in the most recent driver as well, only allowing their specified x8/x8 mode to work. We suspect that enthusiasts will find a way to correct this very quickly.
UPDATE: The Gigabyte 3D1 is a single video card with two 6600GT GPUs. It will only work in x8/x8 (nVidia) SLI mode on a Gigabyte SLI board. However, we did find the 3D1 will operate in x16/x2 mode on both DFI boards with jumpers in "normal" position. We have added test results to our charts with both single 6600GT and x16/x2 dual video mode with the 3D1. The Gigabyte 3D1 provides the interesting possibility of a form of SLI performance on single x16-slot Ultra boards with the SLI mod.
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Dmitheon - Tuesday, January 18, 2005 - link
Kudos to Wesley and the rest of Anandtech for finding this neat little hack. I wish nVidia simply didn't have the Ultra line of boards, and let the economy of scale bring the SLI board down. I'd love to see the amount of money that went into taking SLI down a notch so they could market a less expensive chipset that costs nearly the same to produce. Personally, I'll end up buying an SLI board as more hit the market and competition brings the price down from it's current $190s (just checked pricewatch.com). Why spend extra? The piece of mind that comes from knowing that nVidia is not trying to take a feature I want, away from me. To paraphrase a hookey old public service announcement: "SLi, it's not a right, it's a privledge" ;)bersl2 - Tuesday, January 18, 2005 - link
I'd rather that more nforce4 boards actually *get* to retail in the first place. Some of us don't want an SLI board (yet)...Jahara - Tuesday, January 18, 2005 - link
I'm confused. Doesn't the SLI crossover chip only come with SLI enabled motherboards?Crassus - Tuesday, January 18, 2005 - link
Does that mean that you could use any Ultra-mainboard with only one PCIe slot and run the Gigabyte 2-chip-6600GT in there with that mod?Neo_Geo - Tuesday, January 18, 2005 - link
Yep, reminds me of the GeForce/Quadro hacking possibilities.Hopefully, nvidia will just eventually merge the Ultra and SLI into one product.
In the case of the GeForce/Quadro, they came out with some updated drivers to discourage hacking. Then, when that was figured out, they went a little deeper and physically changed the cores. Now, a software hack is not totally possible on GeForce (I say not totally, because the hack does partially work and gives a geforce most quadro features, but not all).
Wesley Fink - Tuesday, January 18, 2005 - link
#16 -The DFI LANParty UT (Ultra chipset) will sell for about $140 and it can be modded to SLI. The full DFI SLI-DR will sell for about $200. There are Ultra chipset boards that sell for even less than $140, but we don't know yet if they can work as modded SLI yet - and most don't have dual video slots. There are also some very high end SLI baords that sell in the $250 to $300 range.
PetesEscapade - Tuesday, January 18, 2005 - link
Helps to put something in.....I love it. Regardless of nVIDIA's motives, or lack thereof, it is great to see people digging, tweaking, and passing the info along to the rest of us to do with what we will.
NEVER STOP ASKING QUESTIONS!!!
NEVER STOP SEARCHING FOR ANSWERS!!!
Why did man climb Mount Everest? Because it's there. Why try to turn a nForce4 Ultra into a nForce4 SLI? Because it's there!
PetesEscapade - Tuesday, January 18, 2005 - link
bupkus - Tuesday, January 18, 2005 - link
Of course ATI is rushing SLI solution video cards for the nForce4 SLI and now Ultra chipsets. My guess would be their drivers will attempt to exploit the Ultra hack, unless legal advises not. nVidia understanding this and seeing their dilemma of more chipsets vs. more video cards will choose both and rush an nForce4 Ultra version 1.1. If not, ATI's SLIs will force nVidia to allow the hack in their drivers. Could an ATI chipset with a cheaper ATI SLI design open the door for ATI's chipsets?Hehe, lets wait and see.
skunkbuster - Tuesday, January 18, 2005 - link
i wouldn't call $229 cheap. still pretty expensive to me