>>338669546
It was abandoned about the same time SLI got abandoned. 

>>338669709
>>338669715
>>338674006
Dual graphics cards usually sucks because in like 2009 everyone switched to Alternate frame rendering, AFR, where GPU 1 would work on a whole frame by itself, and GPU2 would work on the next frame. The problem should become obvious when you realise it still takes each GPU 1/30th of a second to render a frame, but you're receiving twice as many high latency frames so the stats say 60fps. Multicarding died pretty much a couple years after frame-time analysis tools came out and showed it was a load of shit. Since from the time the frame information was delivered to the GPU to the time it comes out is still 1/30th of a second you're still effectively getting 30fps of latency. 

However, for VR it would actually work since you do actually need two frames at the same time. Instead of one GPU rendering one eye and then the other (or working on both at once) you could have each eye rendering on different GPUs. This would actually increase your framerate since this is effectively split-frame-rendering (SFR) where the per-frame load is split rather than alternating. 

Anyway, tl;dr multicarding is dead, but it'd work for VR which is a shame, but VR SLI is also dead.