No SLI support at launch http://www.maximumpc.com/evolve_lack_sli_support_launch_recommended_specs_revealed Saying that the Alpha ran fine on one 780
I meet the minimum, just. I though the 560 was a fair bit better than the 5770? The alpha ran pretty poor for me. 50GB looks like it's becoming more common annoyingly enough.
Disk space size on most new releases has been 30-40gb. With both the Xbox one and ps4 using blue ray drives expect this game size more frequently now with textures no longer been required to be mass compressed same with the audio. It's a good thing really. Alpha always runs pretty poorly, beta is the performance test as far as graphics go as the differences between beta and launch are quiet small for most games.