Crossfire/Eyefinity help?

[Wishdokkta]

Hi guys, new member, first post

I am at the end of my tether with this now - I have spent countless hours scouring google and various forums and have seen many opinions and issues. I would really appreciate some help!


Ok, first off - the rig:-

AMD FX-8 - 8120 CPU
16gb DDR3
ASUS M5A97 Mobo
2 x MSI R6850 GPU's in Crossfire
60gb OCZ SSD / 2 x 1TB HDD
Kuhler 620 CPU Cooler
OCZ Fatal1ty 750w PSU
Creative SB X-Fi Xtreme
3 x 24" Acer Monitors
Windows 7 64-bit Pro

Clean install of windows, Mobo BIOS updated, 12.4 catalyst drivers installed

So here is my issue. Crossfire and eyefinity (as I have seen from many forums) have many issues but I am yet to see one quite like this, if I use crossfire it is fine, if i use eyefinity it is fine, if I use both together....its woeful

EVE Online is my major problem (Eyefinity certified)

If I have eyefinity enabled, and crossfire Disabled, I can get 60fps no problem at all at 5760 x 1080.

If I have eyefinity disabled and crossfire enabled - I can get through-the-roof fps at 1920 x 1080. Runs like a train.

If I have both eyefinity and CF enabled, I get 7 fps @ 5760 x 1080. If i reduce the resolution to 1920 x 1080 (effectively not using eyefinity), we are back to max fps again, the fps is improved the more i reduce the resolution.


Other relevant stuff :

I have noticed that if I try and run anything in 5760 x 1080 with CF, when i can (eventually) get out of the game, windows tells me the GPU drivers have stopped working and been recovered, it doesnt do this in 1900 x 1080.

I have switched monitors around and that hasnt worked. I am using an active displayport, 3 x DVI.

I have tried a different card (an Asus 6850) - no different.

So I cannot get my head around this. Why can one card handle the graphics better than two?? Obviously I know that eyefinity and crossfire have had their relationship problems but that cant be the reason surely....they are both AMD technologies. I have ruled out VRAM, the general consensus is that 1024 is enough (and in any case, ONE card is doing fine with 1024!).

Any help on this would be appreciated, I know i can get a 7xxx card and forget the crossfire but thats not an option atm.

Why am I having so many headaches with this?

 

[Wishdokkta]

Done some more testing - Dragon Age: Origins in CF/Eyefinity @ 5760x1080 - the second GPU idled at 100mhz but with 80-100% load - suffice to say the fps was terrible.

Any idea at all guys?

 

[whorupeople]

I had a similar issues but with different cards. How many bridge connectors are you using?

 

[Wishdokkta]

I am just using the one connecter to link two cards.

Some developments here.... I can get Dragon Age running in 5760x1080 and EVE running likewise with very decent framerates. However, the second GPU runs at 99% all of the time and eventually my PC freezes up and needs to be restarted. This happens regularly in 5760x1080....

I will test with some other games.

 

[whorupeople]

This is going to sound odd to bear with me.

I had the same problem with two 5750's recently. A friend of mine runs two 6870's with eyefinity as well. We found a fix I will explain below that makes absolutely no sense. But hey what works, works.

In your case, I should point out that your motherboard's second PCIE slot is only 4x. My best guess is that there is not enough info coming from your second card to handle the eyefinity from two cards due to the slow second PCIE slot. Minimum for a decent graphics card like yours should be 8x. Crossfire exchanges data between both the slots and the bridge, which means your card sync is probably getting off which would lead to the problems you are having. Hate to say it but min PCIE setup for xfire should be 8x8. I run 16x8 which works great for me.

As mentioned above, my odd but working fix for my GCs. I added the second bridge of my cards. Not sure why this works - it shouldnt make any improvement more than 1% if at all. But it just made them go up to their full potential. (easily a 20FPS increase) I don't think that will help you much though, because most 6850's only have one bridge slot. (Not sure about MSI)

Is this a new rig?

 

[Wishdokkta]

Yes its a new rig.

From every piece of info I have read, the second x4 slot should only make about 5% difference in crossfire. I can live with that.

My 6850's only have one bridge slot

 

[whorupeople]

I am not really worried about performance loss per say with the 4x. More about card sync. When I tried the 4x slot on my wife's computer to put my old GC to crossfire with her's it kept crashing or freezing every 15 minutes during games. So that's kinda where I got the idea.

Did a bit of research and everything I can find says that 16+4 PCIE just doesn't work with Xfire + eyefinity.

http://www.tomshardware.com/forum/324952-33-eyefinity-wont-work-crossfire

Since the rig is new you should proly just go ahead and exchange the Mobo to a Xfire certified board.

I know it seems like I am pressing the issue here, but honestly I have looked over the setup a few times now (I have two of them in for a customer so i just assembled and looked) and I am not having the problem. Only difference in our setup GC wise is your running a FX processor and I am running a Phenom x4. Shouldn't be the problem... so its gotta be the slots.

Edit: On a side note I have been looking and it MAY be possbile to setup your PCIEs to 8x8 in bios. I can't find the specifics about your mobo on it, but its doable with other ASUS models so it MAY be possible. Sweet build by the way. Exactly the kind of build I like. Excellent performance and OC potential while spending a bit less.