I've been running FFXI using Windower since I got this laptop last July. Currently running 3.41 on Vista Home (came with the machine, XP would have been an extra $170). I have an nVidia 8400M with 128M of RAM using the 169.17 driver. When running a single instance, everything is fine; I can use plugins, run at high resolutions, set a good DrawDistance value, leave all effects on, and get good FPS except in very crowded situations. My machine is a 1.8GHz Core2 Duo with 2GB of RAM.
Recently, I've been trying to 2box a second account. The moment the second POL starts, the first one gets some horrible visual issues. PCs, NPCs, mobs, and animated stuff like lamps, fires, and even doorways for some reason have horrible flickering, with parts of them constantly disappearing and reappearing. Once both windows get at least as far as the character selection screen, they BOTH have the issues. It doesn't matter if I start both windows at 640x480 with everything in FFXI turned as low/off as it can get; the problem doesn't improve. I tried changing the settings in the nVidia control panel all the way to "performance", and that made no difference either. I've tried unloading all plugins from both instances for good measure. Nothing else is running.
I've searched through everything I can find on this site, and Google, and all I saw was one post from several months ago with no replies. If anyone else has encountered this problem, or better yet, has ideas on how to fix it, please let me know.