How often would you hit a block with CPU mining now, mining with a good i7 processor? I mean, is it a matter of hours, days or weeks or... years?
I have 1 4core/8thread and 1 8core/16 cpu mining and I get between 2-4 blocks a day between both of these CPUs. With a single quad core, I would expect 0-1 blocks a day, certainly 3-4 a week.