Just doubled my iMac's ram... no performance gain in CS3

Just got myself a new aluminum iMac with 2.8 ghz core 2 duo with 2gb ram. I ran a benchmark on a simple but hefty CS3 project (an andrew kramer project file) with multiprocessing, and it finished in 3:30 minutes. (With no multiprocessing it was running at around 4:50)

Today I just doubled the ram successfully, and tried to tweak the memory settings to take advantage, and a few issues came up. First of all, CS3 is only detecting 3 gigs (100% mem. usage shows as 3 gb). Secondly, no change at all in the benchmark time, still 3:30.

Here are the memory and cache settings right now, with the 4 gigs installed:

Max mem. usage: 100% = 3.0 gb
Max RAM Cache: 50% = 1.5 gb

Disk Cache Disabled.


PLEASE would really appreciate as many tips as possible to prove to me that I didn't buy that extra ram (and now have to figure out how to sell the original ram) for no reason.