lol nah, the more sticks isn't faster or anything, but like DJ-Chris said, with 2x512 you'll be able to run it in dual channel, BUT that doesn't mean it'll perform faster than the 1gb stick because it will have more bandwidth since it's PC3500, unless like I said the 2x512 PC3200 was like 2-2-2-5 timings and the PC3500 was like 3-4-4-8 which are ridiculously loose and I doubt they are that.
The PC3500 would outperform the 2-2-2-5 dual channel PC3200 if it were say 2.5-3-3-7 timings just purely because of more bandwith although perhaps not by much.