I haven't done any serious 2-boxing in a few years, but I have a rezbot and a small army of dust-gathering alts on a second account.
After coming back to EQ 2 months ago, I noticed that each instance of EQ takes up much more memory than it did just 12-18 months ago. I have 2 Gb of RAM, but EQWin2 gives me a "low memory" warning and I notice a slowdown if one of the toons is running through a graphically intensive zone in SoF or TSS. When I check Windows' task manager, it reports that each EQ instance is using 600-800 Mb of RAM, which is a lot considering that I have all the bells, whistles and Luclin models turned off except for the ones needed for mounts. 1-2 years ago I could two-box just fine on a PC with just 1Gb of RAM, so the significant increase in memory use is puzzling. Load times are also significantly longer when I have both accounts running. Granted, I don't trust Windows' task manager because it doesn't always report actual physical memory use, but the slowdowns and the EQWin2 "low memory" messages appear to match what it shows.
Is there a way to limit EQ's memory use to, say, 500Mb per instance? Should I experiment with PlayNice, another LavishSoft product that I haven't tried yet? The current situation makes it harder to leave an alt in the guild hall to preserve guild portal settings and if I decided to start 2-boxing seriously again, I might have trouble in newer/higher level zones.