Query on additional RAM

Hi,

I currently have an Intel Core2Duo CPU T7500 @ 2.20GHz with 2GB RAM.

I am in the process of installing PI7.1 using VMWare on an USB external HDD. Due to performance issues, I plan to upgrade the RAM.

Will total 6GB RAM give me a leap in performance compared to 4GB RAM, especially since

1. the processor is going to remain the same.

2. I am installing this on an external USB HDD; so the USB port speed should not be a limiting factor in performance...can someone comment on this point?

Thanks

Prasad