I think I found a bug in FurMark 1.18.2.0.
I have single Asus Radeon HD7870 and i5-3550 which have an Intel HD2500 onboard graphics. I use Radeon, and my two LCDs are connected to Radeon, but HD2500 stays enabled. FurMark shows both of them as CrossFire in main screen.
(http://i.imgur.com/z4kScPn.jpg)