HI, I have P3-1.1ghz with 256MB SDRAM (i guess it should be 133mhz--please tell me if it is too??)....now, I am planning to upgrade to 512 MB RAM.... These are my questions: 1. is it OK to put DDR ram with SDRAM 2. is DDR RaM better than sdram and if yes how? 3. and can I put more than 133 MHZ of ram with the one i have ? Thanks.

Go here: www.crucial.com That site will tell you exactly what you can (and shouldn't) use for your particular MOBO.

First of all, no P3 mobo has DDR slots in them. Yours MAY be RDRAM (even faster than DDR, but more expensive). My advice - take the stick to the store and get another 256Mb 133MHz just like yours (in pin alignment), or, check with mobo manual for max amunt of ram. Two types(DDR-SDR, SIMM-SDR pairs) DO NOT work together, the mobo will always choose DDR instead of SDR (even if you have 1 gig SDRAM and 128 Mb DDR-SDRAM, only 128 will show up, but "less of better stuff" isn't better in this case.) only ASUS has the option that utilizes both types. Also, for P3, RDRAM or SDRAM, as long as you have a lot of it(over 384) will work pretty much the same on a single CPU system. Generally, going over 512 Mb RAM on any P3 is not needed, unless again you have a double-CPU board