No wonder... That's meant to be a DX11 benchmark. Also it's a little too new for AMD to have made a crossfire profile for it because the 4870x2 is sadly a bit behind.
BTW, stock clocks for a 4890 are 850/975, so it's possible that that's why the 4890 was closer to the 4870x2.
I see well here's my new benchmarks from Heaven, it only used have my Vram for some reason.
FPS:
51.8
Scores:
1306
Min FPS:
8.3
Max FPS:
136.2
Hardware
Binary:
Windows 32bit Visual C++ 1600 Release Mar 1 2011
Operating system:
Windows 7 (build 7600) 64bit
CPU model:
Intel(R) Core(TM)2 Duo CPU E8500 @ 3.16GHz
CPU flags:
3552MHz MMX SSE SSE2 SSE3 SSSE3 SSE41 HTT
GPU model:
ATI Radeon HD 5800 Series 8.821.0.0 CrossFireX 2048Mb
Settings
Render:
direct3d11
Mode:
1680x1050 4xAA fullscreen
Shaders: high
Textures: high
Filter: trilinear
Anisotropy: 4x
Occlusion: enabled
Refraction: enabled
Volumetric: enabled
Tessellation: normal