Ya gotta love Dell, they just love to sell their overpriced parts. That how they can sell millions of cheap computers. But they all do that. The support guy is right, you need to be sure what kind of RAM you put in your machine. 8100 uses rdram, which runs about double of simm. go to www.centon.com, they have a nice little ram config utility to match memory to your machine. I just chked for dell 8100 and it sent me to the right memory on amazon for $189 for 256 rdram for your machine. This might be more than you want to inves right now but give it a couple of months, memory is getting cheaper all the time and the next change in format is already coming down the pipe.
I dont have the cfs3 on my machine, so not familiar with it, but I run video editing software and you can really see the diferance in performance. If your program needs memory, and its not in ram, then your computer uses your disk drive as extra space. this is slow, it is much better and faster to be able to draw directly from memory. IMHO