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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nitrus - Wednesday, January 19, 2005 - link
what wrong with nvidia making a little money. i'd like to see a healthy ati and nvidia so they would make cards cheaper(older models) and better every six months. if we dont support these companies, then imagine a motherboard with no exspansion slots as companies start to intergrate everything. ati/nvidia are starting to branch out into other sectors, and id gladly support them for "cinematic" graphics. i have an an8-sli i bought for 199.99 from ZZF with a 6800gt and 6600gt so i can run 4 lcds. worth every penny...nitrus - Wednesday, January 19, 2005 - link
Deucer - Wednesday, January 19, 2005 - link
For those of you who are asking for an application for this mod, I have one. I want to play HL 2 now. I don't have enough money to afford an SLI rig, but I can scrape together enough for a 6600GT and this board. This would be significantly better than what I'm running right now. I want SLI as an upgrade path so when the 6600GT costs as much as the 9600 does now, I can buy another one and get a very affordable boost in proformance. And I'm relatvely sure that I will be able to find an SLI bridge within the next year so that takes care of that issue too.Of course this doesn't make any sense for someone who is running Dual 6800 Ultras, this is a cost lowering solution, think about what people on a budget are actually buying and how this could help them.
MarkM - Tuesday, January 18, 2005 - link
Thank you Wesley for the intriguing article & detective work. It's really neat to have a resource who's not afraid to be your guinea pig and risk frying a very precious commodity right now, an nF4 board :)#30 - I don't see why A and B are exclusive -- why can't they keep producing and shipping Ultra chips in current architecture while at THE SAME TIME preparing a change to prevent this mod form working & then jus switch to that when it's ready?
#50 LOL, never spent more tha $200 on a single piece of compuer equipment?!?! I can tell that you weren't buying computers in the 80s!!
Wesley Fink - Tuesday, January 18, 2005 - link
The graphs have been updated with results from a single Gigabyte 6600 GT and the "dual 6600GT on a single card" Gigabyte 3D1 running in x16/x2 dual video mode. The Gigabyte 3D1 provides the interesting possibility of a form of SLI performance on single x16-slot Ultra boards with the SLI mod.DigitalDivine - Tuesday, January 18, 2005 - link
I have never spent anything more than $200 for a single computer equipment. And i don't plan to in the future.Hopefully, Via could get their act together faster and release an sli solution for guys like me on the cheap. Honestly, I bought an Asrock k7v88 at newegg for $50 and it overclocked my 2500+ barton to a 3200+ like a champ, and it was a via kt880 chipset, a very good performance competitor to the nforce2.
i mean i just bought an epox nforce 3 250gb at newegg for $70 for my sempron 3100+ clocked at 2.4ghz, and if an sli solution comes for around $100, i will surely hop on the pci-express boat, and maybe buy an athlon 64.
Wesley Fink - Tuesday, January 18, 2005 - link
#49 - Corrected. Thanks for bringing this to our attention.ALL - I have some very interesting numbers with the Gigabyte 3D1 dual-GPU in single GPU vs. Dual GPU x16/x2 mode on the DFI. As I said earlier, the 3D1 does not work properly in x8/x8 mode in any SLI board except the Gigabyte, but it does work fine in x16/x8 mode on both the SLI and modded SLI DFI with SLI jumpers in normal (x16/x2) position instead of SLI (x8/x8) position. I am considering adding the numbers to the charts.
Azsen - Tuesday, January 18, 2005 - link
There is a possible typo you might like to fix?In the Half Life 2 tests, scroll down to the 3rd set of graphs (1280x1024 4xAA/8xAF).
It has "2 x 6800U x8/x8 (nVidia SLI)" listed twice?
Shouldn't the green bar be labelled: "2 x 6800U x16/x2 (Ultra SLI)" as in all the other graphs?
Great article anyway, cheers. :)
Cygni - Tuesday, January 18, 2005 - link
Ahhh, got it Wesley. I was confused by that.DEMO24 - Tuesday, January 18, 2005 - link
Nice article! Now to get the review of the DFI up so we can all stop wondering what it performs like :(