Breaking the SLI "Code"

With the flood of nForce4 motherboards getting ready to enter the market, we had a decent selection of very recent nForce4 Ultra and nForce4 SLI motherboards. We also had both the SLI and the Ultra versions of the DFI based on the same PCB. With this wide selection of boards, we could look at the differences in the Ultra and SLI chipset and also confirm that they were not unique in any way.

If you look closely at the pictures of the SLI and Ultra, you will see that the chipset themselves appear identical. However, a closer look at the resistors and pads surrounding the chip shows some differences. The resistors appear the same on both, but there are 3 sets of resistor pads that are closed on the SLI chipset while just two sets are closed on Ultra. The vertical set of resistor pads just to the right edge of the chip itself is closed on SLI and open on Ultra. We could find no other obvious differences in the 2 chipsets. Could it be this simple?

We closed the set of resistor pads on the DFI LANParty UT nF4 Ultra-D with conductive paint, as you can see in the photo below.

We set the jumpers to SLI, attached the top bridge from an SLI board, since the Ultra boards do not ship with an SLI bridge, and fired up the system. The system was immediately recognized as an SLI chipset on boot and in Windows XP by our latest 71.40 Forceware drivers. Our little bit of very easy modification had "turned" the Ultra chipset into SLI. We no longer had driver limitations and performance was now exactly the same as the performance that we achieved with a normal SLI chipset.

We also tried modifying an Ultra to SLI with an ordinary #2 pencil. It worked perfectly, and with there being so much room around the set of resistor pads, you don't have to be that neat. If you close the pads, you have converted the Ultra to SLI. Those of you who remember Athlon XP modding for CPU speed will recall how close the sets of pads were in that mod. This required masking and careful painting of the pads to be closed. With the Ultra to SLI mod, there is huge real estate around the resistor on which you are working. As a result, even "all thumbs" modders should have an easy time with this one.

Index Performance: x16 vs. x16/x2 vs. x8/x8 (SLI)
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  • Fluff - Tuesday, January 18, 2005 - link

    Pencil trick to make a Quadro 4000 i would like to see!!!
  • cosmotic - Tuesday, January 18, 2005 - link

    (oh wait)
  • cosmotic - Tuesday, January 18, 2005 - link

    Nice comment Dranzerk!
  • Fluff - Tuesday, January 18, 2005 - link

    Oh come on guys. This sort of thing is nice to know. But would you seriously splash out on 2 graphics cards and scrimp on the motherboard?

  • Dranzerk - Tuesday, January 18, 2005 - link

    Our Take forgot to add...

    Getting SLI at anytime counts are you being a moron for spending so much money regardless of a mod that saves you a few bucks. SLI = Worst nvidia ploy ever.

    I mean come on nvidia, think up something original than what everyone else has did.

  • Filibuster - Tuesday, January 18, 2005 - link

    This reminds me of the Promise Ultra100 to Fasttrak100 mod.

    "Nvidia.... that greedy money hogging .... trying to milk us customers for all our worth."
    Lol...they _are_ a semiconductor company, what did you expext? Last I noticed none of these guys are not for profit agencies...the fun is in outsmarting them (unlock and overclock, unlocking pipelines, turning on sli).
  • Wesley Fink - Tuesday, January 18, 2005 - link

    ALL -
    We apologize for the posting confusion with this article. It was scheduled to go live this morning, but was accidentally auto-posted around midnight by our document engine. We immediately pulled it down and posted this morning as originally planned. That is why some of the comments have odd times for a 7:30AM post.

    We think you will find the information worth waiting for.
  • PseudoKnight - Tuesday, January 18, 2005 - link

    Don't get me wrong. I think this was great investigative work. I just hope it proves fruitful at the retail level.
  • Jii - Tuesday, January 18, 2005 - link

    I knew something like this had to be lurking underneath and here we were again.

    It's great to see that there are people who have the time and imagination to start even looking this opportunity and bring this to public.

    The only drawback is that now Nvidia knows that we know the thing, that they didn't want us to know, that we now know (you know) ;-).

    But seriously: As the modding possibility came to public view, my best guess is that Nvidia will, instead of tweaking their drivers, start modifying the chip structure in a way, that such modifications will become harder to accomplish, completely impossible or will make no difference.
  • Aquila76 - Tuesday, January 18, 2005 - link

    >>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.<<

    Do you have an ETA for the nForce4 roundup? I have a $3K tax return coming and am building an Uber-AMD64 SLI dual-Ultra rig and want to know which is the best SLI for the buck.

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