Quake 1 would have been the driving force, as I recall I had a MX200 Mhz CPU and a Matrox Mystique. I was able to see Quake in all it's 3D accelerated glory however I followed up with a Voodoo card as the Mystique was a little slow.
IMHO I agree with some previous posters, the move to a 1080/1080 Ti would provide the biggest benefit. Note that SLI 1070's would give you a nice boost but SLI "can" be problematic and isnt always supported. Your CPU and RAM look pretty good to me.
This thread got me thinking so I just got my wife a white one for her Birthday/Mothers day too, included the cream smart cover and a clear back shell, she loves it.
May have missed some but basically....
Intel Pentium 70MHz (In an IBM Aptiva)
Intel Pentium 133MHz
Intel Pentium MMX 200MHz
Intel Pentium 3 1GHz
Intel Pentium 4 3GHz
Intel Core 2 Quad Q6600 2.4GHz (one of my favourite chips ever, still viable)
Intel i7 930
Does not include my Color...