catalyst 8.7 doesn't even recognize the video card (i'm pretty sure its not supposed to, since it is dated 20th july and the launch was on aug, 12)
4870 x2 shipped with 8.52 (8.8 beta i think)
i did manage to install 8.52 by cutting/pasting actual driver folder into the whole unpacked setup one.
i still get _m.a.d._ artifacts in 3dmark vantage with aa on.
most other games are okayish
crysis runs like a charm, just a tad slower than on your rig.
it seems that mine is a plug-and-pray type of device ^^
i _really_ hope that first official 8.8 will be installable on this thingy...
could you dump your bios via gpu-z and upload it somewhere? i would really appreciate it.