[Drumstix42]

Well, for starters, your network card really shouldn't hurt ya that much. The big thing is the video card for one, and the CPU for two. EQ2 is much more CPU-heavy. If you have a dual-core you can at least use windows Set Affinity to put each instance on a different core (if possible). Otherwise, just have some good RAM.

You can use ALT+TAB to swap between windows, or just resize each window in windowed mode.
I run two accounts occasionally on one machine, but not for fun. Boxing in EQ2 takes all the fun out for me. EQ1 it was normal to be playing two accounts, lol.