Three-boxed on min settings last night with ISBoxer running. I didn't turn off any background programs (AV, steam, etc.) just to see what would happen, and it ran without a hitch. I was very pleased. Total mem avg usage was 3.25Gb, and pretty stable over about an hour. Neriak spiked it, but even that only brought it to 3.6 or so.

3-boxing it is...I just need to get the hang of hotkeying macros for three toons now.