512meg RAM vs two 256meg RAM

Ok a few quick question before i place my order online.

I am going to purchase a total of 512 meg of ram and want to know if there is any diference in the speed in say two 256meg modules or just one 512meg one.

Won't it take ever so slightly longer to access the data on two 256meg modules compared to one 512meg module?

Also would two 256meg modules CL2 be faster than one 512meg module at CL3? And will two 256meg modules both still run at CL2 on my compatable motherboard?

Thanks all in advance, as soon as i get a few posts i will be placing my order over at Crucial.

Also i have noticed info about refresh rates for ram. 2k 4k 8k, lower being better (faster).

Is there any company making 512meg CL2 SDRAM with 2k refresh rates or if not then what is the most i can expect?

Any info or advice on this matter please post and let us know.
Ive checked Corsair and they only do 512 meg SDRAM CL2 with 8k refresh.

Thanks again.

Getting a larger sized stick is normally always a better idea. This is because larger sticks have more value and are easy to sell a year on from now.

However, because it takes larger modules on a 512Mb stick rather than a 256Mb, it is likely to run hotter, slower and will cost more than 2x256Mb sticks.

I would prefer 2x256Mb Performance sticks rather than 1x512Mb Generic stick.

I got my 2x256Mb Crucial DDR 2100 for £70. Thats damn cheap. Not over a year back I bought 2x128Mb Generic PC133 3-3-3 for a whopping £280

2 sticks 256 CL-2 is better than 1 Stick 512 CL-3. Also Crucial is great memory, so I hear.