ok i'm running a win7 comp 64 bit and a 32 bit DA4 pro last release b4 4.5 with 8 gig ddr3 ram dual 2.1 big processor and a 500gb hdd with 1tb exthd all my content is ( other than genesis) on the 1tb exthd and i havent had much issues with mem lag or leak.  although that doesnt mean i am special or maybe it does but the more background progs you have running on your system does hinder the usage of your mem expecially if you dont have graphics card specific mem ( graphics card onboard mem). windows is notorious for using mem that you cant find out where its being used so is possible that you have more than half your int hdd occupied with your programming and content.  this in it`s own would slow your preformance as well as needing to clean your registry and defragging and optimising your hdd and maybe even defragging your hdd registry.  auslogics has free programs on cnet.downloads.com for registry cleaner defragger and registry defragger that could and most likely will speed your usage and minimize your mem leakage.