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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DrDisconnect - Thursday, January 20, 2005 - link
Does nVidia management have any links with Bausch and Lomb?? They were selling the same exact same contact lenses in two different product channels ie. daily wear and monthly wear. Those who bought daily wear threw out a perfectly good product after a few days, those who bought monthly wear spent a fortune on the same product the daily wear people threw out after a few days.Selling flawed chips (eg. missing pipelines) as a less powerful product I can understand. But this is just outright customer abuse by nVidia.
HardwareD00d - Thursday, January 20, 2005 - link
Maybe Anand can do an article on how to make a custom SLI bridge ;) Maybe someone could create a flexible bridge that could be like a "universal adapter".HardwareD00d - Thursday, January 20, 2005 - link
unless you use the 3D1 card, #62adnauseam - Thursday, January 20, 2005 - link
#28, Please note I went to the DFI site again today and they have CHANGED the picture that was there the other day. It no Longer shows a SLI bridge in the photo. see here: http://www.dfi.com.tw/Upload/Product_Picture/Cable...and here:
http://www.dfi.com.tw/Product/xx_product_spec_deta...
Compare with photo from #28 post. I dont see why more people are not addressing this, it makes the mod worthless if you cant get a bridge.
cryptonomicon - Thursday, January 20, 2005 - link
if the new DFI board is anything like the LP nf3 250gb, it will be the best overclocking board for 939, not to mention this incredible sli exploitWesley Fink - Thursday, January 20, 2005 - link
#57,#58,#59 - The single card/dual GPU Gigabyte 3D1 ran in 16X/2X dual video mode on both DFI boards with the jumper setting at "Normal". As stated in the comments and the article, the Gigabyte would not run in x8/x8 (nVidia SLI) with the jumper in SLI because it requires special BIOS hooks for that mode only supplied by the Gigabyte board.This is not a change from what we described in the review - just more information about alternate modes.
We do agree the single card/dual GPU idea has promise for the future. That is why we tested the 3D1 on the boards and shared results. Even in x16/x2 the 3D1 performance boost compared to a single 6600GT card was significant.
poor Leno - Thursday, January 20, 2005 - link
@ Wesley:But if all the tweaking can make the 3D1 to run on "other speeds"/ config (16x/2x and not 8x/8x), it shows that there is some flexibility maybe... is there not a way in this lifetime to run two 3D1's maybe on 4x8????? 2x8 on one bus and 2x8 on the other? Do you think in the future it will be possible to mod to 2x16??, cause in that way the 4x8 will be possible i think (correct me if im wrong) :P
Pete84 - Thursday, January 20, 2005 - link
#57 My thought's exactly. I thought that the Gigabyte drivers were specially tweaked so that SLI would be running out of a single x16 slot . . .johnsonx - Wednesday, January 19, 2005 - link
To Wesley Fink:What happened to the Gigabyte 3D1 board requiring special BIOS hooks to POST, which only the one Gigabyte mainboard had? I thought that was mentioned at least twice in your original article on the 3D1.
ksherman - Wednesday, January 19, 2005 - link
since obviosly Anandtech doesnt mind soft moding hardware... why not a SoftQuadro mod for the Video cards? I would really like to see an article about the soft moding of the gaming cards to the workstation graphics. Yes i realise that they will not perform as well as the actual card, I wonder how close... Also, since cards like the 6800GT can be used in SLI, It might be interesting to see a SLI workstation setup...