On multithreaded workloads that I care about its not just a little faster, it's a lot faster.
There is still a lot of fruit to be had in that direction I think and that's before you consider the other areas left for performance improvement.
Of course for some workloads/people they are already butting up against a different cost/benefit and they do care about ekeing every cycle out the processor but for me it hardly matters.
My desktop at work runs a development version of our main system faster under vagrant than it runs in production since I've got more RAM and a machine with twice as many cores.
It's a strange market when that happens..
