I have 512MB of RDRAM, and everything seems to run great.  I have heard that 768 would give a noticable difference (especially for BF1942).  Any opinions?

I bumped mine from 512 to 1024 with no HUGE noticable difference.  It did improve the performance a little, but not $200 worth of improvement.  Thats what 512 more cost me.

umm get faster ram... unless youre at something like pc2700 now

Isn't RDRAM the best?  I thought thats what I read when I bought it (a year ago).  I heard DDR was the best value, but RDRAM was faster, I'll have to check the pc#.

SDRAM is cheapest at 133mhz.  DDR is better with speeds upwards of 300mhz now.  And of course RDRam is best with the highest speeds.  DDR ram works just fine though.  I get the same 3dmark scores as other Dell 8200 that use RDRam.  So to each thier own.

Does your Dell motherboard support AGP 8X?  Mine only goes 4X and I want to get all I can out of the GeForce FX when it comes out (Hopefully 1.7g is fast enough)

Nope.  No 8x here.     If I had that, I'd have gotten the ATI 9700.  I'll problably upgrade my motherboard later down the road when the prices go down and stability goes up.

Ya, as much as I want to upgrade; a 1.7 with a GeForce3 just won't be obselete for a while.  I'll wait until the hyperthreading processors are mainstream (and cheaper).

   

Increasing your ram from 512 to 768 probably won't be noticable (speed wise). However, it al depends on what you do. I can tell you that for SOF2, it doesn't matter. If you are running like... die hard 3d graph progs, or mapping programs, you may notice it. Also: if you are running a server which uses a lot of resources you may notice it.

Another thing: RDRAM performs better on most "3d" based tests. However, it depends on your chipset too. Also, an intel/rdram system is more expensive than a AMD/DDR system (which performs pretty good too). Take a look at this:
http://www.tweakers.com.au/articles/cpu_mem/rdram_ddr/page1.asp