1 crossfire bridge vs 2 crossfire bridges [Archive]

zanzabar

09-29-2009, 04:47 PM

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

09-29-2009, 06:57 PM

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

09-30-2009, 01:09 AM

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

09-30-2009, 03:54 AM

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

09-30-2009, 03:55 AM

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

09-30-2009, 04:09 AM

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

09-30-2009, 04:40 AM

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

09-30-2009, 04:58 AM

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

saaya

09-30-2009, 06:42 AM

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*

09-30-2009, 06:47 AM

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

Kensek

09-30-2009, 07:19 AM

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.

http://img525.imageshack.us/img525/1277/1000582g.jpg

ELItheICEman

09-30-2009, 07:45 AM

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 :banana::banana::banana::banana: 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

09-30-2009, 10:25 AM

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*

09-30-2009, 12:01 PM

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

09-30-2009, 01:17 PM

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.

http://img36.imageshack.us/img36/3528/1000615k.jpg

texasreefer

09-30-2009, 03:44 PM

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

09-30-2009, 06:46 PM

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

09-30-2009, 06:53 PM

Razrback16

10-01-2009, 02:44 AM

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. :shock2:

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

10-01-2009, 03:18 AM

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

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

Jakalwarrior

10-01-2009, 07:20 AM

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

10-01-2009, 08:04 AM

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

10-01-2009, 11:32 AM

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. :shock2:
dont get what you mean, sorry :D

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*

10-01-2009, 11:33 AM

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.

demonkevy666

10-01-2009, 12:53 PM

my 3870s won't enable crossfire with out both on, I'm vista 64 bit.

just test out two card with out bridges on the pcb.
cards like the 4350 and 4550, that say they support crossfire should work too if that where the case.

texasreefer

10-01-2009, 04:00 PM

dont get what you mean, sorry :D

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?

Sorry, for the confusion, saaya...yeah, software enabled crossfire. HOw is that done...what software is used?

demowhc

10-01-2009, 04:15 PM

Sorry, for the confusion, saaya...yeah, software enabled crossfire. HOw is that done...what software is used?

the ATi drivers take care of software CF - for low end cards there is enough bandwidth for crossfire without the need for the bridges, you can also run higher end cards but they become bandwidth restricted resulting in less performance...

edit/ I also asked ATi how many bridges to use about a year ago in a support ticket and they told me only 1 bridge is required for 4870 CF..

texasreefer

10-01-2009, 04:18 PM

hmmm, yes i guess not necessary....It seems that for newer cards i.e. 4890, 5870 two connectors works best

IronWarrior

10-05-2009, 01:25 PM

I have two HIS 4670 IceQ Turbo's in CFX, I use two bridges because I thought or was told by people here I think that two are better then one, has anyone really tested this out, would there be any FPS difference betweeen one or two bridges?

MetalWaterBox

10-05-2009, 02:41 PM

villa1n

10-06-2009, 05:38 AM

texasreefer

10-06-2009, 06:40 PM

I was wondering about one or two bridges with my 5870's through my searching on the net I found a review with two 5870's in Xfire and the reviewer said they had contacted ATI about this particular ? and that ONE bridge is all it takes and that using two wouldnt hurt but doesnt really help either...If I can find this I will post a linky.......

http://www.guru3d.com/article/radeon-hd-5870-crossfirex-test-review/3

its under the pic with 2 bridges...lol

WOW, MetalWaterBox, awesome find....

According to the reviewers at 3dGuru...

"Though the photo shows two CrossfireX bridges only one CF strap is actually sufficient and recommended to retain better the airflow of the board. According to ATI there’s really no need for a second one unless you use 3- or 4-way CF."

Verry Interesting :up:

demonkevy666

10-14-2009, 06:38 PM

http://ati.amd.com/technology/crossfire/CF_combo_chart_Nov08.jpg

note cards in pink crossfire with out connectors, on crossfire boards.

Nizzen

10-16-2009, 01:56 PM

I was wondering about one or two bridges with my 5870's through my searching on the net I found a review with two 5870's in Xfire and the reviewer said they had contacted ATI about this particular ? and that ONE bridge is all it takes and that using two wouldnt hurt but doesnt really help either...If I can find this I will post a linky.......

http://www.guru3d.com/article/radeon-hd-5870-crossfirex-test-review/3

its under the pic with 2 bridges...lol

I have 2x Asus 5870 in crossfire. I tested 1 bridge vs 2 bridges in games and 3dmarks. Crysis, farcry 2, nfs shift, crysis Warhead, Fallout 3, 3dmark 05,06 and vantage. All tests where identical with one and two bridges. No performanceloss og gain.

But if I run my 5870 cards in x16 + x8 pci-e speed, then my average fps in Warhead goes form ~53fps --> ~42fps. Compared when I run pci-e x16 +x16 on my Evga x58 vanilla. In 3dmarks I don't loos so mutch "power" from x16/x8.

Apparently Crysis Warhead need all the bandwidt it can get :)

nascasho

10-16-2009, 04:14 PM

I have 2x Asus 5870 in crossfire. I tested 1 bridge vs 2 bridges in games and 3dmarks. Crysis, farcry 2, nfs shift, crysis Warhead, Fallout 3, 3dmark 05,06 and vantage. All tests where identical with one and two bridges. No performanceloss og gain.

But if I run my 5870 cards in x16 + x8 pci-e speed, then my average fps in Warhead goes form ~53fps --> ~42fps. Compared when I run pci-e x16 +x16 on my Evga x58 vanilla. In 3dmarks I don't loos so mutch "power" from x16/x8.

Apparently Crysis Warhead need all the bandwidt it can get :)

Whoa, I guess that sounds right and odd. My board and cards are 16x and 8x but my score are similar with others to a certain extent with Vantage and Crysis... But it runs like garbage. You think that's the cause? What did you do to get different pcie freq? I was debating if my board is the cause of retardness... Crysis, even though it say 40 it'll look like 20

Theorw

10-16-2009, 08:35 PM

I think when i had my 4850 1gig with 2 bridges i d get 1-2 more frames in crysis but then again i am not sure...But chances are that its true...

Nizzen

10-16-2009, 11:00 PM

Whoa, I guess that sounds right and odd. My board and cards are 16x and 8x but my score are similar with others to a certain extent with Vantage and Crysis... But it runs like garbage. You think that's the cause? What did you do to get different pcie freq? I was debating if my board is the cause of retardness... Crysis, even though it say 40 it'll look like 20

When I have a pci-e card in the third pci-e x16 slot, the pci-e config on the three pci-e slots is: x16-x8-x8. When only the first two pci-e slots used, the config is x16-x16-x8.

The third pci-e slot runs only in pci-e x8 on Evga x58 vanilla. Only MB with nf 200(s) have 3 pci-e x16 electrical or more

nascasho

10-16-2009, 11:11 PM

Thing is that the LE is locked at 16x/8x/4x/8x and I get some bad results and get benches on par with others, but the benches are too small to compare spec to spec.

Crysis in general anyways. In some areas it'll lag... really bad. I get microstutter pretty bad too. Game says 40+ fps and it'll look and feel like 20. I also don't hear too many complaints about CFX performance for some reason either, yet my benches are on par... and it sucks.

I dunno if it was because of the 16x and 8x setup or not even the though the bottleneck isn't THAT bad.

P24965

SocketMan

10-17-2009, 08:06 PM

"Dual channel interconnect" is the term (describing the crossfireX bridges) I've heard somewhere.

When in doubt - use 3+ cards and 4 sticks of ram :D;)
http://picasaweb.google.ca/lh/photo/vlmDc-9szp6XyLA3lU4RVg?feat=directlink

texasreefer

10-18-2009, 01:53 PM

Maybe you heard that here http://ati.amd.com/products/radeonhd3800/specs.html

Located under the Crossfire config of the 3800s. NOtsure what that means "Dual channel interconnect is not required for ATI CrossFire, and may not be included in all product configuration."

SocketMan

10-18-2009, 02:02 PM

Yea they even call it "high performance",nice find :up:

I am guessing that maybe in the future there will be a need
for using 2 per 2 cards,probably when a lot of data transfer
is taking place (high resolutions+IQ+6+monitors).

darckhart

02-03-2010, 09:50 AM

sorry to drag up this old topic, but this is my first xfire setup (2x5850), and i was wondering the same thing. i've tried 1 and 2 bridges and the only game where it seems to make a difference is in crysis. BUT 2 bridges somehow makes it worse! the stuttering is more pronounced in certain areas AND sometimes the framerates will drop down to <10 for no apparent reason. removed 1 bridge and played the same part and it's ok. repeatable about 4 times. soo my question, has there been any real consensus? or is it just a per game thing still for now? the other two games i'm playing now (mw2, fc2) i notice absolutely no change between 1 and 2 bridges.

Particle

02-03-2010, 10:00 AM

Just use one bridge. That's the way I think most of us do it, and there's no benefit to using two. It only seems to cause problems.

WrigleyVillain

02-03-2010, 10:36 AM

Heh not railing again you darck it's just this is one of those topics, like whether or not it's a good idea to disable the page file when you have a lot of RAM, about which there is really never consensus and that seems to be a constant source of confusion and questions.

texasreefer

02-03-2010, 11:01 AM

WrigleyVillain

02-03-2010, 12:24 PM

oh well....deal with it! If it bothers you so much then don't respond to something that may concern someone else. Stick that in your 280 and smoke it, deadhead. This post has nothing to do with your old arss ancient setup.

LMAO! And that from someone named texasreefer. ANYWAY, my post wasn't even a complaint really so chill the f out. Just about the fact that this seemingly simple question is never resolved and it's kind of hilarious.

BTW I got this 280 as a straight trade for a 4870 until the 5800 series comes down to earth. Not a bad deal, even a rabid ATI fanboy should be be able to admit.

texasreefer

02-03-2010, 12:29 PM

Good trade...

WrigleyVillain

02-03-2010, 12:36 PM

Thanks. I have ran ATI cards only since X800 and wanted to try Nvidia drivers for a change for IQ comparisons and different AA modes. I kind of hate Nvidia but I'm really glad I did this, there is a definite nice difference in some games.

Actually originally traded for a 260 but it blew up (literally) after a week and MSI sent this nice reference 280 so I got pretty lucky.

Hell Hound

02-03-2010, 03:05 PM

@ Higher res you will notice micro stutter with just one cable,@ least on my 3870 gddr4's.

darckhart

02-03-2010, 03:06 PM

haha alright thx for the input! yea i kind of figured it's one of those perpetually unresolved things. i'll just leave the 2nd one on since it doesn't seem to hurt anything. =)

WrigleyVillain

02-03-2010, 03:20 PM

No it doesn't. For whatever it's worth I Googled this when I had 4850 crossfire and found a bunch of threads all over the place and no one in any of them could prove for sure in every situation whether one or two is "best". I didn't notice any difference in my own testing and chose as well to leave two as I had two and it looked better too. Theoretically, at least, two could provide more bandwidth which could also explain why some people claim they see microstuttering etc with only one in some (i.e. high res) situations.