Tri/Quad crossfire 6900 users

[Callsign_Vega]

In both tri/quad crossfire configs using my 6970's most games crash outright in Eyefinity. Anyone else having these issues? I've tried all drivers from 10.12 to 11.1a hotfix.

[Johnny87au]

Mind posting your hardware?? Also try 10.5

[Callsign_Vega]

2600K
Asus P867 WS Revolution
8GB DDR3
Win 7 64-bit

Quadfire works fine in single display mode. It's in Eyefinity that has all of the problems in tri/quad crossfire. Usually all the games end up with CCC.exe causing an application error, crashing the game and resetting the displays out of Eyefinity mode and to a lower resolution. Does 10.5 even work with 69xx series?

[sniper_sung]

Why people like 10.5? It's the first version which ever changed some fundamental architecture of ATI drivers, from which all the following versions causes inconsistent fps in various games like wow, napoleon total war etc.

Still running 10.3 here as it was released for the most stable version of ATI Stream SDK.

[Callsign_Vega]

Are there any modified old drivers that will work with the 69xx series? I went to install the 10.5's but they cannot detect the 6970's.

[Oztopher]

I'm guessing the cards in just 2 way crossfire work fine in eyefinity? I would just wait for newer/better drivers and official support.

[SoulsCollective]

Does a straight-up two-way Crossfire setup work?

Additionally, have you installed Win7 SP1?

[Callsign_Vega]

Yes, two way crossfire works fine. 3/4 work fine single monitor, but Eyefinity huge problems. Isn't Win7 SP1 still just a release candidate?

[SoulsCollective]

It's RTM, but installing it gave me huge problems running Crossfire and Eyefinity, so I was going to recommend a fresh Win7 install if you had installed SP1.

If two-way works fine, it sounds like you're going to have to wait for a driver update. Price of early-adopter, I'm afraid.

[Roadhog]

works fine here. Maybe you have a bad card. Although I don't have eyefinity so....

[Callsign_Vega]

It's RTM, but installing it gave me huge problems running Crossfire and Eyefinity, so I was going to recommend a fresh Win7 install if you had installed SP1.

If two-way works fine, it sounds like you're going to have to wait for a driver update. Price of early-adopter, I'm afraid.

I did a fresh Win 7 install but did all of the normal updates, not SP1 RC. 4x crossfire works fine single 30", but when I put it into Eyefinity all hell breaks loose and everything crashes. 2x crossfire works in Eyefinity.

If I have to wait for AMD driver updates, thats pretty much saying it will be broken for a very, very long time if not forever.

[SoulsCollective]

Er...no, not really. You'll have to wait at most precisely one month - 11.2 will be out on 28th of February at the very latest. Issues like that are much more likely to be fixed via a hotfix release, though, particularly if you report it to AMD.

[Callsign_Vega]

I forced scissor and tile rendering in RadeonPro but that did nothing to help. I think this problem is at a greater depth than just the screen rendering mode. Single/Dual 6970's only been working Eyefinity, triple/quad 6970's crash the game and give me errors like this:





Some interesting scaling numbers for single 2560x1600 display Heaven 2.1:

1x = 35 FPS
2x = 67 FPS
3x = 102 FPS
4x - 120 FPS

[Neova]

Some interesting scaling numbers for single 2560x1600 display Heaven 2.1:

1x = 35 FPS
2x = 67 FPS
3x = 102 FPS
4x - 120 FPS

Wow! Totally linear scaling! Makes me want to buy another 6950 to unlock but so far my 2x 6950 are fast enough even with 8xSSAA at 1080p. Maybe a 3rd card for Crysis 2 and Duke Nukem Forever.

I found you can get better performance for some games if you load up Radeon Pro, setup a profile for a game and force it to use D3D Friendly AFR while leaving MVPU at default (which would load CCC or CAPs profile for the game if it supports it).

It boosted a lot of performance for some games.

Most DX10/DX11 games don't need this fix.

BTW: How fast and what kind of MB / CPU / RAM do you have?

[Callsign_Vega]

I have a 2600K on a Asus P8P67 WS Revolution but just still at stock speed. Building a chilled water cooler but these damn Eyefinity crossfire problems have been keeping me busy. I hate when things don't work!

[Callsign_Vega]

Well I believe I have found what the problem is with tri/quad crossfire Eyefinity using 6970's on 3x 30" displays. It's a bandwidth limitation on the crossfire bridges.

If I drop the resolution down from 4800x2560 to 3150x1680, quad-fire Eyefinity magically works again. Using Heaven 2.1 which allows custom resolutions, up till about 4000x2000 quad-Eyefinity works. Above that bandwidth, it crashes.

So AMD decided to make their bridges run serial. So this means cards #4,#3,#2 data all has to pass to card #1 over a single bridge which it obviously can't handle at these high resolutions.

From TechReport: "One of those improvements is the ability to combine CrossFire multi-GPU setups with multi-monitor Eyefinity display surfaces. The appeal here is obvious, since pushing 24 megapixels with a single 5870 GPU is possible and sometimes quite workable, but not for every game. Generating that many pixels at the right quality levels would tax any single graphics chip. Making CrossFire work on this scale presents some challenges, however, as AMD readily admits. The core issue is the fact that the dedicated CrossFire interconnect used for passing completed frames between cards has "only" enough bandwidth to sustain a 2560x1600 display resolution. Even three 1080p displays will exceed its capacity."

Another huge design flaw just like the mixed Displayport/DVI-D Eyefinity screen tear design flaw. AMD has some very poor design decisions which will keep me away from them until they get their act together.

nVidia has the right way to design multi-GPU communications, parallel so that all cards can talk directly with each other:




Good thing I have 3GB GTX 580's on order so I can get rid of these 6970's!

[zalbard]

Have you tried connecting the monitors to card #2 or #3?

Also, a very interesting find, I didn't know that.

[Johnny87au]

Well I believe I have found what the problem is with tri/quad crossfire Eyefinity using 6970's on 3x 30" displays. It's a bandwidth limitation on the crossfire bridges.

If I drop the resolution down from 4800x2560 to 3150x1680, quad-fire Eyefinity magically works again. Using Heaven 2.1 which allows custom resolutions, up till about 4000x2000 quad-Eyefinity works. Above that bandwidth, it crashes.

So AMD decided to make their bridges run serial. So this means cards #4,#3,#2 data all has to pass to card #1 over a single bridge which it obviously can't handle at these high resolutions.

From TechReport: "One of those improvements is the ability to combine CrossFire multi-GPU setups with multi-monitor Eyefinity display surfaces. The appeal here is obvious, since pushing 24 megapixels with a single 5870 GPU is possible and sometimes quite workable, but not for every game. Generating that many pixels at the right quality levels would tax any single graphics chip. Making CrossFire work on this scale presents some challenges, however, as AMD readily admits. The core issue is the fact that the dedicated CrossFire interconnect used for passing completed frames between cards has "only" enough bandwidth to sustain a 2560x1600 display resolution. Even three 1080p displays will exceed its capacity."

Another huge design flaw just like the mixed Displayport/DVI-D Eyefinity screen tear design flaw. AMD has some very poor design decisions which will keep me away from them until they get their act together.

nVidia has the right way to design multi-GPU communications, parallel so that all cards can talk directly with each other:




Good thing I have 3GB GTX 580's on order so I can get rid of these 6970's!

Yeah i could of told you that, 30+ you need a dual-link DVI .. I use the one apple sells and bought the display port adapter which slots into the ATI card and other end into the Dual link.. If you search Maxishine in youtube he should have a eyefinity video showing what he uses..

[Callsign_Vega]

Yeah i could of told you that, 30+ you need a dual-link DVI .. I use the one apple sells and bought the display port adapter which slots into the ATI card and other end into the Dual link.. If you search Maxishine in youtube he should have a eyefinity video showing what he uses..

What exactly could you have told me? I run 3x HP ZR30w's in which the 6970's only allow 2x DP and 1x DVI-D connections to them at 2560x01600. Converting the DP signal to DVI-D does not solve any problems, including the screen tear problem.

[Johnny87au]

What exactly could you have told me? I run 3x HP ZR30w's in which the 6970's only allow 2x DP and 1x DVI-D connections to them at 2560x01600. Converting the DP signal to DVI-D does not solve any problems, including the screen tear problem.

Well last year i ran a eyefinity setup with TRI CF on 3x 30" monitors and never had any issues, So i dont think that info you linked is even relevant tbh.. I ran DVI, DVI and DP... http://store.apple.com/au/product/MB...co=MTA4MzU1ODY i use that but also have to buy the mini display to normal display port adapter, works absoulately fine with anything 30+

[Callsign_Vega]

Well last year i ran a eyefinity setup with TRI CF on 3x 30" monitors and never had any issues, So i dont think that info you linked is even relevant tbh.. I ran DVI, DVI and DP... http://store.apple.com/au/product/MB...co=MTA4MzU1ODY i use that but also have to buy the mini display to normal display port adapter, works absoulately fine with anything 30+

I take it they were 5870's? 6970's could be requiring a lot more bandwidth, especially in quad-fire over the crossfire bridge. The connections from the actual cards to the monitors have nothing to do with this problem.

[Chrono Detector]

I'm running dual 6850's in Crossfire and games are crashing on me, now I can see why people are complaining about multi GPU setups, what a nightmare, paid $400 for a dual GPU setup and it doesn't work properly, thanks to poor driver support.

[zalbard]

I'm running dual 6850's in Crossfire and games are crashing on me, now I can see why people are complaining about multi GPU setups, what a nightmare, paid $400 for a dual GPU setup and it doesn't work properly, thanks to poor driver support.

This must be something else, because dual and triple GPU setups work fine for many people (me included).

[Johnny87au]

I take it they were 5870's? 6970's could be requiring a lot more bandwidth, especially in quad-fire over the crossfire bridge. The connections from the actual cards to the monitors have nothing to do with this problem.

yeah 3x 5870s.. Sounded like a similar issue though because i wasnt getting enough bandwidth with just a mini DP + 2x DVI.. I needed a dual link for 30+ monitors..