Intel 550 versus Intel 661

Hi,Since I don't have the cash to upgrade to the Core2Duo system now, and my own now actually still rocks, I wondered if there will be some noticable performance speedup if I go from:Intel Pentium 4 550 3.40GHz Sockel-775 tray, 200MHz FSB, 1024kB CacheTOIntel Pentium 4 661 3.60GHz Sockel-775 tray, 200MHz FSB, 2048kB CacheFrequency I boost anyway, which means that 3.6 I could probably push up to 4.2, but what I am interested in: cache.How important is cache for FS9?And would there be a huge difference between this CPU and Core2Duo E6600? Since Core2Duo has 4MB cache per CPU...but then again, FS9 or FSX don't really use the 2nd CPU.