Hi, I built my system in late August.
When I built it I used an MSI R5830 twin frozr II as the video card.
I recently found a good deal on ebay for an MSI R5850 twin frozr II.
So I bought the 5850 and crossfired them on my Asus M4a89gtd pro/usb3 motherboard.
I have the 5850 as the master card and crossfire x is enabled.
So I go into MSI afterburner to play around a bit and see what I can get the cards up to.
Before I crossfired the cards, I had the 5830 up to 1.220v, 950mhz, 1205mhz and it worked flawlessly.
I checked the box that syncs the overclocking to similar cards, and put the 5850 to the same exact clocks and voltage of the 5830 and it works fine, but the clocks on the 5830 do not change.
Now, I don't know if it will sync the clocks because they are not the same cards, or what.
But the main problem I have is that when I switch the master card to the 5830 in afterburner. As soon as I modify a single setting, even the fan setting up by 1%, the screen freezes and I have to hit the reset button.
I can overclock both card just fine in CCC with amd overdrive, but as soon as I touch the 5830 in afterburner, the computer locks up.
However, I can do whatever I want with the 5850 and have no problems with it.
I also ran MSI kombuster, and it only used the 5850, the 5830 had no load, and the voltage did not change.
By the way, I reinstalled the drivers, CCC, afterburner, and kombuster after I crossfired the cards.
I'm probably just making a simple mistake, or maybe this setup just won't work, even though i've heard of many people who have mixed crossfired successfully.
Oh yeah, I forgot to mention.
After a computer reboot, the first time you open the setting in afterburner, it crashes and said it stopped working.
So I have to click on the desktop icon to open it again, but after that I can open the setting however much I want without a problem, it's just after you reboot it does that once.
I don't know if this helps or not but I think it's worth mentioning.