I currently have 4 GB of DDR2 800 running on my system (Visa x64, Q6700 2.66ghz proc) and my system can handle up to 8 GB of RAM. Will I see a significant performance increase by going from 4 GB to 6 GB of RAM?
(I believe it's currently running 4 x 1GB modules and if that is correct (any easy way to figure that out without opening the case?) my plan is pull 2 of the 1GB modules and replace them with 2 x 2GB modules creating a total of 6GB).
It may depend on whether your programs can use more memory and your use of them demands more. So what programs do you use and what do you do with them?
Also, how much multitasking do you do and how many and what applications do you have working at one time?
How much of your RAM are you using now? While doing what you think are your most intensive applications, open Task Manager (Control- Alt-Delete) and click on performance to see how much of your current RAM you use. If using most of it - go for some more.
You may not even be able to see the full requirement as Vista may throttle back its own usage to make room for other applications, but it should give you a good idea if you are being limited by capacity.
The programs you listed are known to be good multi-taskers and to benefit from the multiple cores so I would think they would benefit from more memory, but I have no personal experience to confirm that.