Have a PC Chips mobo in my new PC. Says compatible with 2 DIMM SDRAM and 2 DDR DIMM SDRAM and DDR supported. Please explain what the DDR is what what type of memory can be used. Is that the same as PC2100?

DDR is Double Data Rate RAM and is usually advertised by its speed i.e. PC2100, PC2700 etc. Your motherboard supports both the old, cheap SDRAM and the newer, faster and more expensive DDR. But you can only use one type at a time.

As for which type of DDR you can use, this depends on the FSB you have set the mobo to.

The mobo is PC Chips 925L. What FSB is compatable with what DDR?

Read the mobo manual, remakable what information it contains.

and i would not try to use SD and DDR at the same time.

:p

i don't have the manual yet. the computer is on order. i'm bidding on ebay so want to know which i should bid on.

i should say, i'm bidding on memory sticks on ebay so want to know which i should bid on. if i wait for the manual then its another few weeks waiting for memory if i order it.

Go to the motherboard manufacturer's web page and look up the memory specs there.

Do you need to use both DDR slots at once? Or can I just put one stick of 512 MB in instead of two sticks of 256 MB?

You can put one stick in one slot, yes. This will leave you space for future memory if you deem it needed. Also, a second stick need not be 512 but can be 256, just in case you ask.

I would also go with pc2100 as this will be guarenteed to be compatible.

Secoast

Mobo is PC Chips 922 not 925 as I stated earlier, which site says is compatible with pc 2700.