Review: CrossFire Vs SLI

[Cooper]

XbitLabs (http://www.xbitlabs.com/articles/video/display/ati-crossfire.html) have made it again. Another huge comparison test. Over 15 games not to mention synthetic tests. So read it and find out what is better for your needs ;)

[eddieate]

Testbed and Methods

CrossFire system was tested in the following test system:

* AMD Athlon 64 4000+ CPU (2.4GHz, 1MB L2);
* ATI RADEON XPRESS 200 CrossFire Edition mainboard (ATI RD480 + SB450);
* OCZ PC-3200 Platinum EB DDR SDRAM (2x512MB, CL2.5-3-2-8);
* Maxtor MaXLine III 7B250S0 HDD (Serial ATA-150, NCQ, 16MB buffer);
* Creative SoundBlaster Audigy 2 sound card;
* Cooler Master Real Power 450 PSU (RS-450-ACLY, 450W nominal power);
* Dell P1130/Dell P1110 monitors (21”, maximum resolution – 1800x1440x75Hz);
* Microsoft Windows XP Pro SP2, DirectX 9.0c;
* ATI CATALYST 8.162.1-050811а-026057Е.

For NVIDIA graphics cards we assembled a different test system. Here it is:

* AMD Athlon 64 4000+ CPU (2.4GHz, 1MB L2);
* ASUS A8N-SLI Deluxe mainboard (NVIDIA nForce4 SLI);
* OCZ PC-3200 Platinum EL DDR SDRAM (2x1GB, CL2-3-2-5);
* Samsung SpinPoint SP1213C HDD (Serial ATA-150, 8MB buffer);
* Creative SoundBlaster Audigy 2 sound card;
* Cooler Master Real Power 450 PSU (RS-450-ACLY, 450W nominal power);
* Dell P1130/Dell P1110 monitors (21”, maximum resolution – 1800x1440x75Hz);
* Microsoft Windows XP Pro SP2, DirectX 9.0c;
* NVIDIA ForceWare 78.01.

Those test rigs are hardly fair, they give crossfire 1gb of cas 2.5 ram and the SLI rig 2gb of cas 2 ram, whats the idea there?
Both setups should be exactly the same apart from the motherboard and GPU's
/Ed

[Vapor]

X-Bit has kinda always had problems making it fair, no?

[drcrawn]

Those test rigs are hardly fair, they give crossfire 1gb of cas 2.5 ram and the SLI rig 2gb of cas 2 ram, whats the idea there?
Both setups should be exactly the same apart from the motherboard and GPU's
/Ed

They said they had issues getting 1gig sticks to boot on the XFire board.

Nevertheless, doesn't look good for ATI IMO.

[eddieate]

I wouldnt say it looks that bad, the x-fire managed to keep up in most situations even beating the 7800gtx SLI in some places,
for a new technology and some last-gen cards thats not bad.
but still thats no excuse for the delays in x-fire and the R520.
/Ed

[nn_step]

They said they had issues getting 1gig sticks to boot on the XFire board.

Nevertheless, doesn't look good for ATI IMO.

then why didn't they run both rigs with 1Gbs at 2x512mb?
I want even benchmarks...

[eddieate]

yeah ^^ seems stupid when your testing GPU's to use diffrent ram,
I could understand if they were testing AMD vs Intel or something and COULDNT use the same...
/Ed

[Kunaak]

what people need to remember, is crossfire X850XT PE's should not be compared to SLI 7800 GTX's. those cards were never meant to go against each other.

it should be compared to the SLI 6800 ULTRA's if anything...

[Arkangyl]

With all the talk about which dual-card setup is faster and which has the better percentage increase i thought I'd just re-mix some of the most used info. Taken from X-Bit are the numbers, all games are @ 1600x1200 4x16x. First is the card name, then single, double cards; the percentage is the percent performance a dual-card setup has vs. a single card.

These games were picked because they possesed some of the most strenuous engines. Source [HL2] and the Doom 3 engine will definatly be marketed and used in other games; FEAR has been killing top end rigs since the demo came out and Far Cry's Crytek engine has just flat out impressed.

Doom III
X850 XT
28.2, 51.7
183%

6800 Ultra
37.5, 59.3
158%

7800 GTX
46.2, 69.7
150%


F.E.A.R.
X850 XT
24, 24
100%

6800 Ultra
26, 39
150%

7800 GTX
31, 46
148%


Half-Life 2
X850 XT
75.6, 92.1
122%

6800 Ultra
73.2, 97.8
137%

7800 GTX
101.7, 106
104%


Far Cry
X850 XT
56.9, 78.8
138%

6800 Ultra
48.2, 71.7
149%

7800 GTX
58.4, 83.9
144%


My take on the percentages is that ATI did a great job catching up in Doom 3, however beyond Doom nVidia's SLI platform seems to net the larger increase from the second card [the exception being dual 7800 GTX's in HL2, however after 100fps things do seem to be a tad CPU limited]. The other key bit is how dual X850 XT's match up to a pair of 6800 Ultra's. I was impressed with ATI's CF Doom 3 performance as it closes the gap on what was a nVidia dominated engine. At this point Half-Life 2 seems like it's becoming CPU limited; HDR ought drop all the numbers though. ATI doesn't appear to have a Crossfire profile of FEAR ATM thus making me wonder about ATI's claim to universal improvement, nVidia's SLi offers a solid 50% increase however. Far Cry looks to also be highly receptive to dual cards; performance seemed relatively similar with all cards.

Hope this helps someone

[Thorry]

Seems kind of sad to test the Crossfire rigs @ 1600x1200 since the refresh rate will be terrible. Also if you only have a refreshrate of 60 hz it's stupid to render more then 60 fps, just turn on v-sync and go @ 60 fps... don't need a crossfire setup to do that.

But it has to be noted:

The limitition has nothing to do with Crossfire itself, if you upgrade the DVI chip you'll have greater resolutions and refresh rates. So Ati will make sure the new cards will have the correct chips on there.