32bit/64bit? ReadyBoost Or More RAM

I have been running build 7260 for awhile on my Asus notebook (see system spec) and so far have not had too many issues with it. Since I have done several succesive upgrades: Vista Business > Windows 7 build 7227 > Windows 7 build 7260 I have noticed some bugs creeping in (apps and games are crashing periodically or not loading correctly, gaming performance could be better). I attribute this to the string of successive upgrades.

I am going to wipe the drive and do a clean install of either the 32 or 64 bit RTM build in the next few days as it becomes available. One of the main goals is to increase performance with both applications and games. I use this laptop for work doing web development and heavy photoshop and graphics intensive work. I typically have many applications open at once using quite allot of system resources.

For this project I am going to:

A: Add another 2gb of ram to bring the total from 3gb to 4gb, or

B: Add a fast 16gb sd card to the system for the ReadyBoost feature, probably using around 6 to 9gb for this feature

For me to add the extra gig of ram it becomes more necessary to install the 64 bit build. If I use the 16gb sd card for ReadBoost, I can probably stick with 32 bit. None of my apps are currently 64 bit anyhow so I am not sure 64bit is the way to go right now.

I would like to hear people's thoughts on this and what others experiences have been especially using ReadyBoost on systems with over 2gb of memory..