P2210H are the three I have. One off DP and two off the two DVI ports in the back of the 5870.
Yes Eyefinity works fine in Windows XP/7 for a display resolution of 5760x1080.
Ubuntu 10.04 was strange. When installing, it used the 2nd DVI monitor to the right. After install and reboot, it used the center DP monitor. Once I loaded the ATI 10.4 drivers, the 1st DVI and DP monitor (left and center) work fine.
xrandr detects three monitors, but always throws crtc errors when trying to work with the second (right) DVI monitor.
If I unplug a monitor (doesn't matter which) it will work fine with the two monitors that are plugged in no matter if it's DVI/DVI or DVI/DP (even tried VGA and HDMI with the above combinations and that produced the same results)
I can boot over shortly here and get some exact numbers if you want to see them (xorg.conf and xrandr output and all that) but I've spent about 15 hours so far trying to get things up and going and while the two monitors @3840x1080 definitely works great, I'm spoiled to three
for me with an HD5750 its sadly the same! 3 monitors attached (dvi, hdmi, dp) , only 2 working.
xrandr is displaying all 3 , but if i want to enable more than 2 i get crtc errors.