What Ram for a Dell desk top?

I do not have the manual for my Dell I would like to add Ram. What Type Ram would I need to buy to install in my Dell desk top computer? the model on the case states:
Model # DHM
Serial # JDNYD11
mfg date: 041602

If it matters.......The mother board has a sticker with a bar code and the words:
REV. A01

the mother board has four slots for RAM.

The RAM that is in the mother board now are two sticks and the only info on the sticks is this:
Samsung Korea 0214 128MB / 4
MR16R1624AFO- CK8 800-45 011

Can some one tell me what the 4 , that is after the 128MB represents?

There are only two notches in the RAM sticks, and these are located at the middle of the stick, and not near the ends.

Can some one tell me the speed of the Ram I should buy to add to what Ram I now have.......and do I buy high or low density Ram for this computer?

the current RAM sticks have a piece of metal attached with the words Warning Hot Surface and the letter: H


I am running Windows XP home edition.
Thanks to all who help!
4-21-2010

 

Go to www.crucial.com. It will read your machine and tell you exactly what you can, and should, add. :wave:wave

 

i will, ......Thanks a bunch for the tip!!!

 

Looks like you have the dreaded RDRAM or rambus modules installed. Good luck finding these they need to be installed in pairs and if all slots are not filled you need terminating blanks installed in the empty ones. Here are the specs of your modules: Rambus In Line Memory Module, 128, 400M, 64X16, 4C. max per slot is 512mb you probably have 2x128mb installed plus two blanks installed in the other slots.

Hope this helps