Lee has stated that he wants this to run on GPU's rated at around 750 on the passmark. That still includes quite a few people.
The update to Visual Studio 2015, was to be able to have more tools to optimize the core engine with. also making very compatible for other features. If less bottle necks can be found, then every body wins.
Having a card that is capable of DX 10 and above will keep you in the game for a while, before technology just makes our boat anchors more of a hindrance then a help. Also, holding back the capabilities of the engines progression.
My system is 8 years old and all the upgrades I could put into it. But as nice as it runs, within the next few years, it is just not going to be able to keep up.
Upgrades are relatively cheap in comparison to 8 years ago, and for the same money spent then, you can get 100 times the machine today.
See my specs in the sig below.
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit