I have 4GB of RAM but the problem really is that I use a 32 bit OS (Windows XP) so I can choose between having everything in one process and have a limit of around 1.5 GB or having all plugins in different processes and have a limit of around 3.1 GB. However, the latter method have considerable overhead per plugin so it’s often still not enough, especially because my problem usually is not that I use particular plugins that use a lot of memory (there are some though, e.g. Drumasonic for Kontakt) but that I tend to use a lot of different plugins, partly because I often need to use different panning for multiple simultaneous sounds from the same plugin which requires duplications as I wouldn’t like to render the plugin to an instrument, losing its flexibility.
Certainly I could switch over to a 64 bit Windows 7 but this involves quite a lot of work, reinstalling everything (and requires some money for the OS).
I thought I was not the only one struggling with such issues and hoped this could be nicely handled without too much effort but I may be wrong. 