1 crossfire bridge vs 2 crossfire bridges

[SuperPhrank]

Any difference between 1 or 2 crossfire bridges with 2 cards in crossfire?

[zanzabar]

unless u have more than 2 cards then using more than 1 connector will result in the loss of multi monitor support and some random errors.

just use the 1 closest to the IO panel

[texasreefer]

Yeah, when the 1900s, 2900s, and 3870s were out I was using two interconnect cables. Benchmarks, especially 3dmark06 scored much higher with one, and since then I only use one. The 4870X2s only have one interconnect rail on the card, so that supported my thinking. I've noticed that the 5870s have two rails, as do the 4870s. There hasn't been any controversy over it so i'm sure that the 5870s use one interconnect, that is unless more than two cards are used, in which case the 6 rail multi-connector is used. I haven't seen a 3rail single configuration cable, but then again there is prob. one out there.

[Darxide]

I've always wondered why some people use 2 bridges.
I've never had any issue using only 1.
I always assumed the cards had 2 connectors so that the 'middle' card in tri-fire could connect to the card above, and the card below. Hence the X2 cards only have 1, because they only support max 2 cards (4 GPU's)...

[Razrback16]

unless u have more than 2 cards then using more than 1 connector will result in the loss of multi monitor support and some random errors.

just use the 1 closest to the IO panel

What do you mean by random errors? Is there an actual performance difference that is measurable?

[texasreefer]

I think the reason is that a lot of reviews (when dual cores were the thing) were done using two interconnectors. It was also a time of great non-compatability for crossfire. Triple crossfire at that time was called TRiple-Play, and the third card was called a Physics processor. It never took, and there hasn't been true triple crossfire until now with the x58, and other newer chipsets that are out there with the release of the new I7 board line-up.

Speaking of...When are you going to join team Quad-Fire?!?!

What do you mean by random errors? Is there an actual performance difference that is measurable?

I have noticed Micro-stuttering, tearing, and performance loss on 3dmark06

[Russ_64]

Good to know, as the same question crossed my mind after seeing the pics in the 5870 review on TPU (which shows 2 bridges on 2 cards....).

[demowhc]

What do you mean by random errors? Is there an actual performance difference that is measurable?

I had flickering artifacts with an old 2900 CF system using 2 bridges, removing a bridge solved the problem with identical performance.

However I get no artifacts with my 4870 CF system with 2 bridges but I still only use 1..

[One_Hertz]

I had problems with CF not working at all in some games with two bridges back on 2900XT CF.

[saaya]

texasreefer, 4870x2 has one cause the other one is hard wired on the pcb
same for all dual gpu cards...

interesting that 2 bridges cause problems!

[chew*]

Hmmm guess it depends on what cards are used.......IIRC my 4890's will not engage crossfire with only 1 cable.

[Kensek]

Hmmm guess it depends on what cards are used.......IIRC my 4890's will not engage crossfire with only 1 cable.

That's strange my Asus HD4890's worked fine in XFire with only one bridge between the cards.

[ELItheICEman]

I always wondered about this.

Two bridges hasn't caused any issues for my setup AFAIK. That's not to say I haven't had some weird happen before, but I wouldn't exactly pinpoint the dual-bridges as my first suspect. Might be worth some benching with one bridge vs two.

[Stoner133]

Well I use two bridge connects on my 4870's and haven't had any problems. I use two because the directions that came with my cards said to use two. Not only did it say to use two it showed photos of the installation and it used two.

[chew*]

That's strange my Asus HD4890's worked fine in XFire with only one bridge between the cards.

[IMG]http://img525.imageshack.]

Might be an XP 32bit thing......I know the issue was in XP.....it would not even give me the X fire tab.

I started talking mad crap to my mobo becasue i thought i lost another PCI X slot after a ln2 session.......then I realized the wife should be wearing an I'm with stupid T shirt....noticed only 1 x fire cable was installed......added second one and was good to go.

I would say only needing one derives from OS......vista allows more than 2 cards...so in trifire you only use 2 cables......4870 x2's in crossfire only use one cable.

[Kensek]

Might be an XP 32bit thing......I know the issue was in XP.....it would not even give me the X fire tab.

I started talking mad crap to my mobo becasue i thought i lost another PCI X slot after a ln2 session.......then I realized the wife should be wearing an I'm with stupid T shirt....noticed only 1 x fire cable was installed......added second one and was good to go.

I would say only needing one derives from OS......vista allows more than 2 cards...so in trifire you only use 2 cables......4870 x2's in crossfire only use one cable.

I actually had 3 of them. X-Fire (2 Cards) ran fine in 32-bit XP, Vista and Win7 and 64-bit Win7. And I only used 1 Bridge

I ran Tri-Fire in Win7 (both 32 and 64bit) and it only scored 900 more 3DMark06 points than 2 at standard settings. But with 3 cards you need to run a bridge from one to the other to the other.

[texasreefer]

texasreefer, 4870x2 has one cause the other one is hard wired on the pcb
same for all dual gpu cards...

interesting that 2 bridges cause problems!

Saaya, Does that mean that you can runn X2 Crossfire with no external interconnects? Would that be a faster interface? I remember talk about an internal connector/interface, but that talk kinda dissipated.

Just home from work...missed a good rally

[MaK2000]

The 4870X2 has no external connections. You only need it if you are running two of them. It is all traces in the PCB.

[texasreefer]

THis whole thread is about crossfiring ati cards...by external connection I'm talking about the Crossfire Bridge. Hence, by internal connection i'm talking about crossfiring without a EXternal crossfire bridge.

[Razrback16]

THis whole thread is about crossfiring ati cards...by external connection I'm talking about the Crossfire Bridge. Hence, by internal connection i'm talking about crossfiring without a EXternal crossfire bridge.

The answer is no -- if you use more than one physical card, you need a bridge. He's just saying with a stand-alone 4870X2 all the Crossfiring is done on the PCB with no wires leading away from the card. 4870X2 cards have one Crossfire connector as you can only do 2 4870X2's in Crossfire for 4 GPUs -- you cannot go beyond that.

[Slagathor]

Hmmmmm, currently running with both ribbon thingys.......

After work I will have to do a little testing.....

[Jakalwarrior]

You guys read the HardOCP 5850 review? they said at high resolutions they had texture issues and ATI told them to hook up the second bridge which fixed it.

[One_Hertz]

You guys read the HardOCP 5850 review? they said at high resolutions they had texture issues and ATI told them to hook up the second bridge which fixed it.

I was actually testing one bridge versus 2 bridge thing on my 5870s and with a single bridge my rig locked up on the first 3d06 test... Performance was the same though. May have been just some random issue but I ran 3d06 like 10 times with 2 bridges with no issues.

[saaya]

THis whole thread is about crossfiring ati cards...by external connection I'm talking about the Crossfire Bridge. Hence, by internal connection i'm talking about crossfiring without a EXternal crossfire bridge.

dont get what you mean, sorry

and yes, sli works without any bridges and xfire should as well, havent tried it in a while though... they will just transfer the data via pciE then, its called software xfire/sli... it works well but usually a tad slower than propper bridge sli and xfire...

about people who needed 2 bridges... maybe you needed the second bridge?
maybe the right one has to be in place or the left one, bot not both?

[chew*]

I actually had 3 of them. X-Fire (2 Cards) ran fine in 32-bit XP, Vista and Win7 and 64-bit Win7. And I only used 1 Bridge

I ran Tri-Fire in Win7 (both 32 and 64bit) and it only scored 900 more 3DMark06 points than 2 at standard settings. But with 3 cards you need to run a bridge from one to the other to the other.

[IMG]http://img36.imageshack.us/img]

hmmm interesting kensek, might be bios related then as well.

Saaya I will check, i'm tending to think bios or board used can make a diff as well.