Not An Answer
But, it is pretty amazing to see recent Intel CPU dies performing so differently...
But, they're not. When looking at the benchmark graphs from the solved answer, it becomes evident that the real problem behind the varying degrees of system requirements for modern games falls squarely on the devs.
Metro Last Light? i7 killed the G3258? @ 4.8 ghz? Pretty old game sorta?
Yeah. It did.
Thirty-somethings like myself remember learning to code with memory and capacity in mind.
Apparently, the current crop of kids making games never learned The Art of The Tweak.
Going on purely gut instinct, I'd say you're witnessing a great example of programmers actually doing an excellent job!
Last Light is scaling on the i7, due to the fact that it has additional cores. Not only that, but I'd also speculate that you would see a significant effect on this result if you were to tamper with the Hyper Threading capabilities.
This further solidifies any doubt:
1. That devs have become lazy. They often seem to fall back on features such as core emulation and load balancing to mitigate the inefficient coding and memory utilization.
2. That game developers are lazy. Crap, sorry, I lost my place.
.. Wait.. No.. Actually I didn't.