Hey thanks for the CPU chart.
I used this to scout out some old computers and found some old used Dells (THB 6800) with a i7 3770 cpu available.
Running this 24/7 I can mine about 4.5 GRC a day and this matches up with what I figured from your chart.
One point I think you could point out is threads, it seems like the more threads you have the better (even if the processor runs a bit slower) because each extra thread means you can run an extra job.
So something like a i9 that runs 6 X CPUs with 12 threads or the AMD 1700 with 8 cpus and 16 threads would be even better BUT a lot more expensive.