It uses multicore, it just uses the extra threads for rendering distance and AI I imagine.
Still bound on up the main thread however.
Also AMD driver woes transferred over to Windows 7 so rejoice 8.1 users...
Evidently I'm doing something incredibility unheard of trying to mine with one card while gaming on the other...
Edit:
Ugh, good many deities that was flipping two days of pain.
As I said 13.11 was just as bad on W7 as W8.1... Well that's not true, it was actually worse. It got to the point where I couldn't even boot with the driver working, ati BSOD.
Reverted back to the last driver before they miffed ULPS (which is somewhat the issue I was having, either it would shut off the PC or it would crash the driver using 99% gpu at start up), which was 13.6 Beta 2... I couldn't do that with Windows 8.1 since it is pre support
Anyways, it seems to work as it's supposed to now so now to test the performance impact of mining the second card if any...
Oh graphics settings, everything to the right. Except AA, using SMAA and no AO.
Mining:
Not Mining:
Low Res Same Graphics Settings: