Memory types

[FlashHarry]

Hello all,
I want to add some more memory to my ageing pc. Its an amd k6 500mhz running on a QDI Superb1 mother board and currently has 1 stick of 64mb 168 pin pc100 DImm SDRAM. Looks like I can get 128mb for about £17 these days but on Dabs.com there are three different types of 128 sticks:-
128Mb 168Pin DIMM PC100 SDRAM Non-Parity CL2
128Mb 168Pin DIMM PC100 SDRAM ECC Unbuffered CL2
128Mb 168Pin DIMM PC100 SDRAM ECC Registered CL2
Which one do I want to buy? And what does non-parity, unbuffered and registered mean?

Any advice gratefully received.

Flash

[Fingers]

I've never heard parity described like that before?

Parity is somewhat like ECC (Error Correcting Code) in that both types check for memory errors, but they do so in a slightly different way. Both parity and ECC memory have an extra chip on the module to handle the error checking.

For all practical purposes, unbuffered is the opposite of ECC, but not in a purely technical explanation.

Most modern computers that are not servers use unbuffered non-parity memory.

An excellent source for learning about memory is the Crucial FAQ (http://support.crucial.com/scripts/crucial.exe/faq) , Crucial Library (http://www.crucial.com/library/) and the Crucial Glossary of memory terms (http://www.crucial.com/library/glossary.asp)

[This message has been edited by Fingers (edited 08-16-2001).]

[jaida]

you will want the 128 mb pc100 CL2. You don't need ECC for your memory. None of those sticks are parity so you don't have to worry about that. Parity means that 2 identical sticks of memory are required to funciton one cannot work without the other which is why it's referred to as parity.

sorry I forget what unbuffered and Registered refer to.