i7 3770 vs 3930 for Lightroom 4

.... Because in today's RAM marketplace it might be about the same price as 8 gigs.

When I began to build my PC I spec-ed it with GSkill 8 GB, on sale for about $48.  By the time I gathered all my parts, a couple of weeks later, Patriot 16 GB was on sale for about $51.

In my case, I was giving up a couple of GB to my on-chip GPU.  I'm sure 8 GB (6 GB) would have been fine, but you never know.

--
Gerry