Hmmm...For the Office apps, probably not unless they are running truly massive applications for the products (e.g. Full encyclopedias in Word, a very large database, or Excel running tons of macros and/or calculations). The GIS systems I have no experience with, so I don't know how valuable they would find the extra memory.
Your best bet would likely be to download some sort of performance monitor and see where the system bottlenecks are. I have used Perfmon from Systernals in the past. It is not the most user friendly, but it does get the job done. There is another I used, but I can't remember the name. It was more pictorial, so it was more meaningful to me. If you search the net a bit, you get hundreds of hits, but I still can't find it...