I just recently bought and installed two 6870s. (one of the power wires was damaged on delivery, thank god I had a spare!)
Though I have to note that I had 2 screens before the installation of the cards, and with the new cards i have added a third monitor.
The problem is that im seeing worst performance now that i have a 3 screens, though the real issue is that i cannot tell if Crossfire is activated. in the catalyst control center it is check off as "on". also when you click on the secondary card, there is no gpu activity, clock speed, or anything. so Im kinda worried.
You have a huge resolution now, regardless of whether you have 2 6870s or not, the 6870 was and still is nothing more than a decent mid range card. Cant add more real estate without taking a performance hit.
I've recently went to triple monitor as well with XFire 6870's. I was surprised the I can run BF3 with this setup on medium settings. I do plan on upgrading to a 7950 at some point, though.
So, chances are that XFire's working fine, just that these cards aren't the greatest for the setup. GPU-Z will definitely tell you for sure.
To swap from EyeFinity to a single, just make 2 different profiles in CCC. That's what I do.
Over the weekend I swapped out my AMD 945 with an i5 2500k. I knew there'd be an increase in FPS, but I didn't figure 20% in multiplayer! With the 945, I could only manage 28-30FPS in Eyefinity in BF3 on low. Now with the i5, I get playable rates on medium. So the CPU will make a difference as well in some games.
so now i should over clock to a stable 3.5 or 3.6? i think i should!
My processor is a 1055t, i heard that it is very easily overclockable, is this true and does anyoen have an easy step by step guide for this?
Run GPUZ as mentioned while gaming and you can easily see whether both cards are getting usage.
I run crossfire 5850s and ran eyefinity for a little while at 5760x1080. BF3 was easily playable at medium settings no AA, High textures and a couple other features at High (FXAA for sure, and some objects detail I think). It was very steadily in the 40+ FPS range so that's around what you should expect.
And yes if you connect the TV with HDMI then you can flip from 3 monitors to the TV and back. I'd suggest just leaving it disabled until you want to use it though otherwise I don't think Eyefinity will work.