So, I found it quite difficult to get legitimate information on the web in one place regarding a Crossfire Setup with Eyefinity. I want to take the time to help others understand the pros and cons, and answer any questions people encounter.
Please keep in mind, throughout this post I am referring at all times to an xfire/eyefinity setup. And that despite what exact GPU's you have (58XX) you will experience similar issues.
First off, my setup:
Core i7920 @3.6ghz
6gb DDR3 1600mhz
2x Radeon HD 5850
OCZ Agility x2 Raid 0
WD Blacks x2 Raid 0
So, my computer is no slouch. As you can see I'm running a great CPU with 2 5850's in crossfire.
I am using 3x Acer 24'' Monitors, 1920x1080, for a total resolution of about 6000x1080.
Prior to owning 2 5850's I was able to run eyefinity just fine, however I wanted a bump in my AA and AF capabilities.
I also want to note that for anyone wondering about Display port Adapters, the 'Active' non-usb-powered dongle from sapphire/powercolor work great at supporting a 1080p resolution.
First Most Common Eyefinity Error:
The monitor you chose to use your display port adapter on SHOULD BE the middle monitor in your triple monitor array. I have seen nothing but issues with people trying to configure otherwise.
People commonly look at their GPU usage when using an xfire/sli setup and notice one of their cards is hardly doing anything. If they alt-tab and check the GPU usage of the slave card during a game, it frequently lowers the GPU usage on the spot and it looks it its not being utilized. This is a MYTH.
I recommend downloading GPU-Z and allowing it to write a logfile of your GPU usage during a game, this way you don't have to worry about an overlay-or alt-tabbing. If you check the log of the slave GPU after a game session, you will indeed see it is being utilized.
Next- The most important point I can make today:
Micro-stutter is real! It is a never ending, ongoing problem with Xfire/sli setups! You don't hear people complaining about it much with Eyefinity because it is fairly new. Let me be the first to say that without tweaking your setup, you will notice EXTREME micro-stutter when using a crossfire/eyefinity setup. Here is how to fix it:
First and most obvious solution is to enable V-SYNC in any game that you play.
Second, this one is odd, but true. There are two processes that Catalyst Control Center runs, one of them being itself : CCC.exe , the other is called MOM.exe which is monitoring software. Ironically enough, these two processes send interrupts to your video card about every 5 seconds causing micro-stutter.
In your task manager, end CCC.exe and MOM.exe processes.
In MSCONFIG, turn off CCC as a start-up process and neither MOM or CCC will spawn when you reboot.
The common misconception is that CCC.exe & MOM.exe are needed to run games. They are not, all you need to run games in crossfire/eyefinity are basic display drivers from AMD. CCC is simply a suite to make your videocard experience more enjoyable.
So if you want to tweak things, open up CCC, but end the process before you game.
So, in conclusion:
Is crossfire/eyefinity worth it if you have to deal with these bugs? Well, there are two answers, yes and no. Yes is the answer if you are interested in your games looking fabulous. Currently I can play BFBC2 at 60fps all high settings x4AA and x4AF on 6000x1080. You simply must be okay with some hickups along the way. If you'd rather not deal with a newly developing technology, I would recommend sticking to one video card for now.
If you're like me, and enjoy trouble shooting and reaping the rewards, I highly recommend CrossFire and Eyefinity to anyone.
Hope this was helpful :-)
Thanks for comments, apparently there is no longer an issue using your display port monitor(s) in positions other than the center monitor.
A new fix found:
So, this will only apply to those with a xFire configuration... If you're like me you have probably attempted to disable xFire to see performance differences in games. Common CCC bug is after disabling xfire your monitors will drop in brightness, and even after re-enabling xfire the brightness stays low! What the heck!?
Why would the displayport have to be the centre screen? That doesn't make any sense to me.
Unless you have a monitor that natively supports the display-port interface it has to be the middle monitor. To be honest, this was a bug that a big deal several months back, AMD may have fixed this problem.
However it really doesn't affect anything, as there is no quality difference between the monitors that you can notice.
So far I understand everything you said and I would just like to say thanks for putting the time to explain this to us but I was wondering, can the setup have all 3 displays using DVI? Because my monitors only accept DVI and VGA and I've heard VGA has a limited resolution and is lower quality. Thanks alot!