amd never made and will never make a 2.5ghz barton...2500+ is a performance rating the processor only runs at 1833mhz...
Next amd processors use 200/266/333/400 mhz fsbs...
while intel uses 400/533/800mhz fsbs...
the diffrence is that intel runs a quad data rate bus and amd runs a dual data rate bus...you will not find a 800mhz fsb amd board or cpu for a long time!
And this dual "thing" dual channel effectivly doubles the bandwith of 2 or more sticks of memory by using 2 memory controlors...it is good for a 5-10percent performance increase on amd boards (more for intel)
moving on...ddr 333 is best for cpus that run a 333mhz fsb...just as ddr400 is best for cpus running a 400mhz fsb...you will notice that the best memory speeds (for amd cpus not intels) come with the memory synchronous to the FSB...i would only recomend going for ddr 400 for that setup if you are overclocking....
If the motherboard has dual channel support then you can run it however you want...you can use 1 memory module and dual channel will be automatically disabled...you can run the board with 2 same brand/size modules and take advantage of dual channel...or you can run 3 modules in single or dual channel mode...your choice i would recomend dual channel as it does help on most boards...
I personally would buy an Nforce2 chipset motherboard that has ddr400 support...that way you can upgrade to a 400mhz fsb cpu...
boards i would recomend
asus a7n8x deluxe feature rich very pricy but it is from the industry leader in mobos
epox 8rda+ a great cheep board...opposite of the asus board above has everything you need nothing you don't and is an excellent overclocker
Abit nf7-s is a mixture between the epox and asus board great for overclocking and has a few more features
before i recomend any memory i must ask
are you planning to overclock/ upgrade to a 400mhz bus cpu in the future?
3 386DX-25's...12 volts...glue some ln2 and a wicked amount of overclocking and you get a willamantee minus 36 pins, 33.75 million transistors and a couple hundred mhz... :cool: