I have mainboard that supports dual channel memory, (AMD 64 socket 939). I have 512mbram I am thinking of dubbling memory. What is dual channel support? `Will there be a marked improvement in performance when I put in the extra 512 mem unit and activate the dual channel"ing"? How is it different from a normal 1024mbram?

Far Cry, Doom 3, Unreal Tournament 2004, Grand Prix 4

by using dual channel you double your bandwith with your ram. with single channel and pc3200 ram you have 3200mbs bandwith. with dual channel and pc 3200 ram you have 6400mbs bandwith.

p4 at 3330mhz
256mb pc3200
80gb wd hdd
geforce 4 mx440 teporary
Audigy 2 ZS
dvd and cd burner
only 15 so i am tight on cash

dual channel support basically means just that.
it transfers data more effectively,ive seen memory effiency icrease about 10-15% on my dual channel rigs for base ddr.BUT onless the module you have now is dual channel you will have to buy new mem modules and you should buy them in matched pairs.corsiar,o.c.,kingston plus many more sell decent d/c modules.try to make sure the mem clock is the same as you procs fsb.I assume your procs a 400 mhz fsb so i'd use Good d/c 400 and you should see faster load times in games and maybe slight increase in fps.so yes if you have the $$ go for it

amd 64 3000 939 msi neo2 platinuim 1gig ddr 400 winxp