windows 32bit operating systems can not see and use more than 4 gigs of ram. that is why most folks (like us) use 64bit windows 7. if you had a 64bit os and more ram it very well may help but I'm not sure.
I have a somewhat older build (early 2008), 8 gigs ddr2 with a core 2 duo 3ghz and SINGLE cam hd footage stutters in vegas 11