ATI outfitted three motherboard manufacturers with fully functional CrossFire demo systems to show off at the show. The systems featured an ATI CrossFire reference board and a pair of graphics cards: a Radeon X850 XT and a CrossFire Radeon X850 XT.

The CrossFire X850 XT had a DVI dongle with two ports; one connected to the monitor, the second connected to a DVI cable, which was fed into the DVI output of the regular X850 XT card.

Even in CrossFire mode, the two graphics cards appear independently in device manager, which may allow for multi-monitor operation while in CrossFire mode:

Enabling CrossFire is done from within the ATI control panel, and unlike NVIDIA's SLI, no reboot is required:

With CrossFire enabled, the new AA modes are available for user selection:

Armed with one of these machines that ATI sent to their partners, we managed to get some benchmark time with CrossFire. Unfortunately, we didn't have much time to test nor did we have a full suite of benchmarks, so all we could run was Doom 3 (it was either Doom 3 or 3dmark 05).

The system that we used for testing featured an Athlon 64 FX-53, 512MB of memory and the two X850 XT graphics cards running under Windows XP Professional.

We ran all Doom 3 tests with 4X AA enabled at the High Quality presets in the unpatched retail version of Doom 3.

Even at this early stage, performance and stability were both impressive. The system that we were running had just been assembled hours earlier and didn't crash at all during our testing. In fact, the system was so new that the motherboard manufacturer who let us test with their hardware hadn't even seen it running - it was their first time as well as ours.

The performance of the solution was equally impressive; at 1024x768, the dual GPU CrossFire setup improved performance by 49%. At 1280x1024 and 1600x1200, the performance went up by 72% and 86% respectively. We had our doubts that ATI would be able to offer performance scaling on par with what we've seen on NVIDIA's SLI, but these initial numbers, despite being run on early hardware/drivers, are quite promising.

The Problematic South Bridge Pricing and Availability


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  • Panndor - Monday, June 13, 2005 - link

    Lets hope that this endevor by ATI doesn't end up in the same situation at the RAGE Fury Maxx they came up with. The last time they tried this they screwed it up and then cut support for the card like it never existed.

    Looks promising, but I could see problems if they allow different hardware to run in a combined mode as well.

    Competition is good so maybe this will bring down the price of the boards and the cards now.
  • vision33r - Wednesday, June 1, 2005 - link

    Those 2 X850XT PE cards add up to $1000+ alone while price of 6800U are going down.

    I think the biggest prob is not if this works or not, is if the mainboard performance is sacrificed due to the ATI north-bridge. I don't gave 90% of the time on my system, I can't sacrifice losing system performance for gaming perf.
  • xsilver - Wednesday, June 1, 2005 - link

    what's funny is that a few months after the xfire is released, nvidia will probably announce SLI v2.0 and then everyone will talk about how that's so cool Reply
  • Wesley Fink - Wednesday, June 1, 2005 - link

    #49 & #50 - The Uli 1573 we've seen paired with Crossfire DOES suport NCQ. this was confirmed this afternoon with engineers here at Computex. The upcoming ULI 1575 southtridge supports both Sata 2 and NCQ.

    We also saw demos of Splinter Cell on Crossfire with the 2.0 Shader. The demos were at 1280x1024 with all eye candy enabled. Frame rates in the various demos were 118 to 120. Since we did not have reference benches for Splinter Cell, it didn't make much sense to publish these results in the launch article. What we have seen is very promising, but we need more "hands-on" benchmarking before we can say much more.

    Wesley Fink
  • mkruer - Wednesday, June 1, 2005 - link

    #51 That is the real question to be answered. My guess is that ATI will work on a SLI board and visa versa unless there is something specifically in hard coded that prevents the second slot from being used by anything other the chipsets manufactures video card, which is highly unlikely. From the BIOS and driver standpoint the MB is either has 1x16 PCIex slot or 2x8 PCIex slots. Reply
  • elecrzy - Tuesday, May 31, 2005 - link

    its possible to have Crossfire work on the NF4/945/955. Its just that ATI won't support them through the drivers. Sigh... Reply
  • kmmatney - Tuesday, May 31, 2005 - link

    Does the ULi southbridge have NCQ support? Reply
  • weblizard - Tuesday, May 31, 2005 - link

    No Sata II or NCQ support. That's all I need to know to NOT want a crossfire system. Reply
  • bob661 - Tuesday, May 31, 2005 - link

    I had the Abit board with the AMD chipset on it. Worked flawlessly. I gave it to a friend when I upgraded that box and it was running until last year when he upgraded his box.
  • sprockkets - Tuesday, May 31, 2005 - link

    26# That was the 760MPX or the dual processor chipset. Don't recall any irongate issues (that was 750, 760 was the DDR version, right?) Reply

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