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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Klaasman - Tuesday, January 18, 2005 - link
What would be sweet is TWO Gigabyte 3D1 for a total of four GPU's.mclearn - Tuesday, January 18, 2005 - link
Wesley,Are there any visible differences in the DFI Ultra and SLI boards? Maybe the fix for this is as simple as the chipset's "upgrade"
Deucer - Tuesday, January 18, 2005 - link
cnq - Tuesday, January 18, 2005 - link
Wesley,Nice article, and thanks for switching your SLI measurements to 12x10 & 16x12 (I savaged you for including 10x7 in a prev review, which probably no SLI user will both with).
One suggestion for future FarCry runs on SLI: please try with the magnificent eye candy setting "HDR" enabled (new with FC v1.3). It looks great, but is a graphics card crippler -- and thus the **perfect** test for a 2x6800U SLI system.
Wesley Fink - Tuesday, January 18, 2005 - link
Unfortunately the Gigabyte 3D1 dual-gpu 6600GT does NOT work on the DFI when trhe jumpers are switched to SLI mode. The nVidia driver sees that the system is SLI-capble, but it does not recognize the 2nd GPU as there for SLI. This is true with 66.93, 70.90 and 71.40 drivers. If the Gigabyte single-slot dual-GPU would work with more boards they would sell a lot more of them.However, the Gigabyte 3D1 in x16/x2 mode performs quite well when jumpers are left in normal mode. After the mod to SLI it works fine with drivers to 70.xx.
crazyeddie - Tuesday, January 18, 2005 - link
It would be a little late in the game for Nvidia to go back and do a whole lot of reverse engineering to the NF4 SLI chipset to make it less moddable (new word?). Nvidia will:A) Let the NF4 Ultra out the door as is, eat the lost sales of more profitable SLI chipsets, and take solice that their graphic card sales will be quite brisk. This presumes they can actually ship enough video chips to take advantage of the increased demand.
B) Dry up the current supply of Ultra chipsets and go back to the drawing board to disable them more thoroughly. They will miss out on shipping Ultra chipsets to motherboard manufacturers, which may or may not cause contract problems. It would ensure the continued desirability of the SLI chipset at higher margins, however.
I've personally been hoping for an inexpensive PCI-E board for the 939 Athlon 64 platform that I can pair with a Radeon X800XL solution. This news story jeapordizes the shipment of the NF4 Ultra if Nvidia is determined to protect margins for the sake of overall volume. I guess it's no loss to me, because I couldn't buy an X800XL right now anyway.
I guess we'll have to wait and see whether Nvidia wants to focus on volume or margin-per-unit.
Wesley Fink - Tuesday, January 18, 2005 - link
#22 - Your idea was so intriguing I had to give it a try. With the DFI UT Ultra modded to SLI, jumpers in normal (non-SLI) position and the Gigabyte 2 gpu 3D1 I was able to run SLI fine with drivers up to 70.xx. This suggests that the Gigabyte Dual 6600GT might run in the single slot of any nF4 Ultra motherboard in a "semi-SLI" mode. That means 2 video cards are potentially NOT required. Modding to SLI woujld enable a wider range of working drivers. More testing needs to be done before reaching any conclusions.I am getting ready to try the Gigabyte 3D1 now in full SLI (x8/x8) mode to see if that works on the DFI.
ChiefNutz - Tuesday, January 18, 2005 - link
#23, #27 I dunno, when you go to the DFI website, it shows a picture with the link in the box contents on the ultrahttp://www.dfi.com.tw/Upload/Product_Picture/Cable... for the box contents, and
http://www.dfi.com.tw/Product/xx_product_spec_deta...
for the main product page. It's sitting right there in 3 of the 4 pictures right below the Package listing? What gives?
adnauseam - Tuesday, January 18, 2005 - link
the one I think everyone is missing is....where do you get a SLI bridge, without purchasing an actual SLI board. Remember the bridges ship with the boards not the cards, because the spacing between the PCIe slots could be different on each maufacturers board. It seems the only way to get one would be to wait until someone who doesnt plan on using it sells one on ebay. unless........there is a way to purchase a replacement....Ill have to check that out actually.............razor2025 - Tuesday, January 18, 2005 - link
This is awesome find. It gives us more choices. I was planning to buy a NF4 board, so I can use the X800XL I have in pre-order. I didn't want a SLI-ready setup, because the cost is too much. However, if I can get a SLI-capable board (after hack) like the DFI UT for around $130-140, I'll definitely go for them. Most single SLI NF4 boards are fetching around $130-140, and if DFI UT and the Epox board retails for around the same price, everyone who wanted a single SLI NF4 will changed their decision to these awesome boards. Even though I won't be doing SLI anytime soon, I'm sure there will be capable and cheaper cards that can run SLI on these boards down the road. If that doesn't happen, oh well, I still needed a PCI-E board that use Athlon64.