How much DDR do I need

I was wondering how much DDR do I need,I am curently running 768 SD/133 and want to make the switch,my board supports both,but want the DDR,but with christmas im short of cash,so how much can I get away with,I play N3 and N4,so how much should I get?Also what is the difference between registered and unbuffered..
Thanks

Well...

You do realise that DDR is only 10-15% increase from SDRam?

Ram prices since December have boomed and I wouldn't recommend buying now.

But to run Windows XP and your games very good you'd require at least 384-512DDR to run it correctly. Anything lower wouldn't be good.

You mean 10 or 15% better performance,or price wise?

10-15% faster, as in performance.

I am so tired of everyone saying you need buttloads 0f ram to run winxp or any os and games for that matter. Look i have winxp pro, and at startup with only the OS and default services started it only uses 86mb or memory, and i have all the kidergarten looks and everything. Win Xp is just a little more bulky then 2k, my 2k Partition boots up defaulat at like 76mb. Games use up the most. But still I use WinXp and Play games (Counterstrike, Unreal Tournament, Diablo 2, and Command and Conquer, Red Alert 2.) And i have 256 megs of ram, and I NEVER get a hiccup at all. I play games while using seti, or burn cd's and listen to mp3 while running seti. Huge amounts of ram are NOT NEEDED. Unless u are using very graphic intenive apps live AutoCAD, or similar software, you NEVER and i mean NEVER need, or use more than 512mb MAX!!! Some Of the most intensice PC games dont use more than 100mb of mem, so When i play cs on winxp - winxp-86mb, cs-88mb, that is a total of 174 mb. Leaving 82 mb free on my system. heck to use up 256 mb with everyday appz youd have to have every prog on your puter opend up about 5x. Like Winamp, Seti, MSn Messenger, Aol I...ya know things like that that only take up like less then 10 megs

So are you saying stick with my PC 133 memory,or go with 256 DDR?

Well, if you want to stick with whats been around for the past year...hey, its your choice. I went with ddr just cause sdram is gonna be phased out soon anyway. Might as well keep up with the Jones' AND get the 10-15% increase, eh? My 2 cents.

~A

Ok thanks that what i will do..Appreciate it..