3DMark
3DMark is the latest version of this hugely-popular synthetic benchmark. Making use of DX11 features such as tessellation, compute shaders and multi-threading, it provides modern-day results and is available as a free download.
The two Sapphire R9 290X Vapor-X cards are locked together in both benchmarks, and this tells us that a larger framebuffer doesn't come into play in 3DMark.