Video Card and Dual Monitors

[SODAPLAY]

Hi,

I have Geforce4 Ti4200 64 DDR which has a bit faster memory.
I'm going to upgrade it to GeforceFX 5900XT 128DDR, which isn't the best on the market but almost as good as 5900 or if overclocked 5950.
I have several questions here:

1. Tommorow I'm going to buy 2nd monitor and my geforce ti4200 can support 2 monitors, however when I tried connecting 2 monitors (took 1 from a friend) the lightwave would start and run everything smothly, but then I either drag a window or something like that and perspective view becomes very laggy. And I have to restart. My card has only 64 DDR ram which could be the problem or it could be latest nvidia drivers (53 something...). So what do you think, what do I need to fix with my current Ti4200 in order to have 2 monitors connected and run without glitches or problems at all?

2. Does 5900XT 128 runs good with lightwave and is it capable of supporting 2 monitors? Does 128 DDR ram help with showing more poligons without lag than 64 DDR ram?

Please answer as soon as possible I don't have much time. I'm gonna buy monitor anyway, but if you know what could help me please tell anyway. It is good to have 2 monitors when modeling :)
Thank you in advance.

- SODA

[mrunion]

Maybe this will help some?

http://www.bigpony.com/dualmonitor/dualmonitor_nvidia.html

[SODAPLAY]

Thanks for the tip.
That isn't problem. I just want to know what could be done to prevent gf ti4200 from becoming laggy with 2 monitors before I get 5900XT.
Any user of 5900XT or SE please tell me if you're expereincing any problems with lightwave as well.

Thank you.

- SODA