LINK >>
A comparison of cpus at same speed; with one having L3 cache and the other without. This is the conclusion page. Lots of interesting testing was done from the first page to the last.
The link says something very interesting about cpu speed working in the L3 cached cpus favor as speed increased.
Is there a blanket statement that would conclusively say you do not need L3 cache? No such answer is really valid. You can do pretty good generally without L3. It is more economical to not have L3 cache. In real world applications, the performance results would tend to favor having L3.
EDIT: overclocking is going to depend on the motherboard. Most of the time when people start going toward a 'cheaper' processor; they also go with a cheap motherboard and windup with a motherboard that does n0t support overclocking very effectively. END EDIT.