Morphing nForce4 Ultra into nForce4 SLI
by Wesley Fink on January 18, 2005 7:30 AM EST- Posted in
- CPUs
Our Take
It really did not come as a surprise that nForce4 Ultra and nForce4 SLI are the same chipset with some capabilities in Ultra turned off. We have seen many cases over the years in which a manufacturer has one CPU-die or one chipset come off a production line, which are then differentiated with laser cuts or some other means of controlling speed or capabilities. What did come as a surprise is how very easy it is to reverse the process - to turn the nForce4 Ultra into the higher-priced and better-performing nForce4 SLI. This is an extremely easy mod for almost anyone.We suspect that there is more to the story, however, than just the fact that the chip can be modded to be seen by the system as being an SLI chip. nVidia design specifications actually dictate a different board design for Ultra than for SLI. We stated early in this article that DFI is using the exact same board for their SLI and Ultra versions of nForce4. We know that the mod works on the DFI LANParty UT nF4 Ultra-D, but we did not have any other dual video slot Ultra board on which to test the SLI mod. We are expecting the Epox board any day, and we will certainly let you know if the SLI mod works on that board too.
The other surprise is how very close the x16/x2 dual video mode is in performance to the nVidia specified x8/x8. Performance ranged from a worst case of 88.8% of "true" SLI in Half life 2 1600x1200 4xAA/8xAF to slightly better than "true" SLI performance in Far Cry. These numbers are good enough that you can understand why MSI, DFI, and Epox were all planning to release dual-video boards based on the nForce4 Ultra chipset. With nVidia doing everything that they can in Forceware drivers to disable support for Ultra SLI, we can also well understand the reluctance of many manufacturers to try to bring Ultra SLI boards to market.
The discovery that the Ultra chipset can be easily modded to SLI removes a major obstacle to SLI performance on the cheaper Ultra boards - if the manufacturer made provisions for SLI. Once the SLI mod is complete, the system and nVidia drivers see the chipset as a full SLI chipset. This removes the driver issues and the ability of nVidia to turn off support in "non-complying Ultra SLI chipsets".
The DFI LANParty UT nF4 Ultra-D will sell for about $140. With the simple mod, it is a fully capable nF4 SLI motherboard. As you will see in our upcoming reviews, it is also one of the most enthusiast-friendly boards to land on the market since the DFI Socket 754 motherboard. For now, the only board that we know which can be fully converted from Ultra to SLI is this DFI LANParty UT, but there are others on the way, and we are sure it will not be the last. As new Ultra boards with dual-video capabilities arrive, we will let you know if they are up to the conversion task.
When we first found out that an nF4 Ultra could be morphed into an SLI, we felt like kids in a candy shop. The feeling was much like the discovery almost 2 years ago when the Intel 865 chipset could have PAT enabled, so it performed like the 875. In this case, the payoff could be on the order of 25% to 80% performance increase with full SLI compared to single video card performance - much better than the few percent performance improvement that made PAT the must-have feature on 865 boards.
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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