Honestly after my experience with G10, I stopped using it, VRMs just kept getting too hot. I would suggest looking into EVGA's AIO GPU solution and if it would fit a reference GTX 980 Ti if you have a gigabyte reference model that is.
I don't believe DX12 will require new hardware.
I think that's why is driver EOLing products. So that all [if atleast most] DX11 cards will be able to run DX12.
The GoldSrc engine [half-life 1's engine] was built off Quake 2, This looks like when HL was just a Q2 mod.
The final version was it's own engine basically, Interesting to watch, Some of the textures made it into final, Character design seems mostly intact. GoldSrc engine was born from the...