With VST Synthfont, only one instance of a bank is loaded regardless of how many tracks access it. In my case, I used the Fluid3 GM loaded as the default for most of the tracks. I then use another .SF2 for guitar and piano. This is now the default each time I use the synth. If you want to use sounds from different libraries, each will get loaded. If memory is an issue, you can extract the sounds you want and load those instead of the entire library. I never ran out of memory on my old XP system (1.5 gb). I can't answer for Win7 as I'm suffering still with Vista.

I think you'll be happy with Forte. I prefer it over Synthfont for my needs.

R