Hardware is fine, it is the software, that has to take advantage of more threads and cores.
Safari will not be snappier on an eight or twelve core machine anyway.
What applications do you normally use?
Most often, four cores is enough for most, but sometimes the extra cores in a well programmed application can give that a severe boost.
I currently work on video and audio, simple stuff, and during exporting I would like to have many, many more cores to shave some minutes off the wait, but during everything else my four core i7 will hardly gasp.