Fellow Compaq owner here as well, dealing with the same question. Frame rates challenge my patience at times. Using the external cam is brutal and the event cam isn't even a consideration. All this while running on the lowest possible setting. I have:
Evo D300s
P4 1.5mhz
512 ram
Radeon 7500
So, what's a guy that's been playing sub sims since the days of Gato to do? Well, he'd love to drop $$$ on a new comp, but can't stomach it right now. I decided to buy a new card and some more ram. My 9800 Pro and additional 256k arrive tomorrow.
I'll let you know how much better it gets.
Of course, if you don't hear from me in a few days, you know it's gotten much better.