Can someone explain Crossfire to me?

Crossfire and Eyefinity are two separate things. Eyefinity (the use of more than 2 monitors on an AMD card) requires those monitors to be plugged into a single card. When using Crossfire, all monitors must be plugged in to the primary card. This means that if none of your monitors natively support Displayport, you will need to purchase an ACTIVE adapter to change the displayport or mini displayport from the card to DVI.

Crossfire enables the simultaneous use of 2 or more graphics cards. These cards work in conjunction with each other ... it's not quite twice the power, but it's certainly stronger than one of the cards alone.

MD CrossFireX (previously known as CrossFire) is a brand name for the multi-GPU solution by Advanced Micro Devices, originally developed by ATI Technologies. The technology allows up to four GPUs to be used in a single computer to improve graphics performance.

pretty much.

Actually, Eyefinity does work without Crossfire or the active displayport when using 2 cards. However, I definitely agree that he should do as you said, as it is the only way to get both Crossfire and Eyefinity to work together.

@OP,

CrossfireX allows two cards to work together to render frames for games. It can improve performance greatly, up to 100% improvements. However, disabling CrossfireX is preventing you from gaining this advantage. You need to do as Spaniard described to enable CrossfireX with Eyefinity.

simple makes u capable of running 2 same cards together for somethimes double performance.

same technology as sli but made by ati.

Hmm. Apologies for my lack of knowledge. But can someone break down exactly what I will need to do or buy to get Crossfire to work?

My monitors are:

1x http://www.lg.com/us/monitors/lg-E2360V-PN-led-monitor
2x http://www.lg.com/us/monitors/lg-W2343T-PF-lcd-monitor

Let me know if you need any more info.

Spaniard United was correct on what you need.

You need to connect all 3 monitors to the top card, and one of those cards must be connected with an "active displayport adapter". You might also need a mini-displayport adapter to displayport.

So I plug 2 monitors into the top card using regular dvi cables, and then I plug the third one in by using an active displayport adapter? Wouldn't this be putting a lot of stress on 1 card?

yes thats right, it would but its possible. ur not running tri screens for gaming, mostly for i dunno what but if its not gaming ull be fine.

I do casual gaming but nothing extensive and no highly gx demanding games. I just want to run all 3 of my monitors but also get the benefit of crossfire. If I am correct, using crossfire will improve performance by allowing for better rendering and more FPS?

depends if you run crossfire with 2 lower cards. somethimes a single card solution would be better.

whats your full system specs?

and budget

Computer Specs:
-Windows 7 Premium 64bit
-Crosshair IV Formula Asus Motherboard
-AMD Phenom II X6 1090T Processor 3.21 GHz
-Corsair 8GB (2x4GB) DD3 Ram
-Two Saphire AMD Radeon HD 6950s 2gb
-Coolit Systems Eco CPU Water Cooling System
-XFX 850W Black Edition Single Rail Semi Modular ATX 12V 70A 24PIN ATX PSU 80Plus Silver
-Western Digital Caviar Green 500GB HDD
-Seagate Barracuda 3gb HDD (Secondary Drive)
-Azza Case

And then the monitors I already mentioned above. Let me know if you need anymore info. As for budget, I can probably buy what's needed.

you already got great videocards. i see no reason to change anything.

Yes, but in order to run my 3 monitors I have to disable Crossfire in the Catalyst panel. If Crossfire was enabled wouldn't I get much better performance?

Just displaying the desktop on 3 monitors is very little stress at all. The only thing special is that the memory clocks cannot drop to ~300mhz when idling, but that happens with 2 monitors as well. In gaming, both cards work at rendering frames. Don't worry about it, if you want to make use of your two cards, that is how you do it.

I run a 3 monitor setup using 2 4850's. I'll try to answer all your questions.

You can run 3 monitors with 2 cards, however when running crossfire only the monitors connected on the primary card will function. This is why for my setup I normally have crossfire disabled. If I run a game that needs the power of crossfiring then its simple to disable my second and third display and enable it.

Crossfire basically boosts your graphics card performance. It's a way of using 2 graphics cards to do the graphical processing work. The second card in a crossfire configuration is basically controlled by the first card. It does not allow you to span games across multiple screens. For spanning games google SoftH. Great program and with your setup you will love it.

For connecting a third card you basically connect the top and bottom cards to the middle card using one cable each. (Cable from the bottom card to the middle, then another cable from the middle card to the top.)

http://www.kegetys.fi/SoftTH/ this might help

Okay, so in a nutshell... If I am gaming, enable crossfire and just let my 3rd display be turned off. When I am browsing, working on assignments, etc, just disable crossfire to have access to all 3 monitors?

yes. than when u need 3 monitors disable crossfire and have fun.

yep.

u got it dude

Keep in mind, you won't be able to use Eyefinity when gaming this way.

No problem, I don't think any games I play are compatible with Eyefinity. Also, I just ran a quick test playing a game with Crossfire Enabled and Disabled and didn't see any real significant difference in my FPS?

depends some games arent optimized for crossfire or sli.

Crossfire won't help in windowed mode.
If you use v-sync, your FPS get capped at your refresh rate, which might also not show any real difference.
If you have FPS beyond your refresh rate, you won't really see a difference, as the monitor can only display FPS up to its refresh rate.

this is true,