|"Product: Ecs (elitegroup computers) P4vmm2 "|
Your mboard has two types of ram slots - two slots are for SDram (the original SDram) - two other slots are for DDR (DDR SDram - the second generation of SDram).
DDR = Double Data Rate - because of the way the module is wired up, it in effect runs at double the rate of SDram - so, e.g. 133mhz DDR ram runs at 266mz on the module.
You get better performance from this mboard model if you install DDR ram (DDR SDram) rather than SDram.
You must install the DDR ram (DDR SDram) in the slots for DDR ram.
The slots are the same length, but the ones for DDR SDRam ram have more contacts in the slots and on the modules, and DDR ram uses a lower voltage.
SDram slots have two bumps in the bottom of the slot, the modules have two notches you must line up with the bumps.
DDR (DDR SDram) slots have one bump in the bottom of the slot, the modules have one notch you must line up with the bump.
You install one type of ram or the other, not both - you have only a max two slots you can use.
If you install DDR ram in a SDram slot, it won't work, and the higher voltage in the SDram slot may damage the module.
If you install SDram in a DDR ram slot, it won't work, but the lower voltage in the DDR ram slot probably won't hurt the SDRam module.
Ram that works in another mboard , or any ram you buy or have lying around, may not work properly, or sometimes, not at all - even if it physically fits and is the right overall type (e.g. SDram, DDR, DDR2, etc.; PCxxxx, xxx mhz) for your mboard. In the worst cases of incompatibilty your mboard WILL NOT BOOT all the way with it installed, and the mboard may not even beep - the ram has to be compatible with the mboard's main chipset, or in the case of recent mboards, compatible with the memory controller built into the cpu.
See response 5 in this for some info about ram compatibilty, and some places where you can find out what will work in your mboard for sure:
Correction to that:
Once you know which module ID strings (part numbers) work in your mboard, you can get them from anywhere you like that has ram with those ID strings.
If you have brand name ram, it is usually easy to look up whether it's ID string is in a list of compatible modules found by using your mboard or brand name system model number.
If the ram is generic, that may be difficult or impossible.
E.g. Kingston's list of modules:
Part Number Description Price
KVR133X64C3/256 256MB 133MHz Non-ECC CL3 DIMM
KVR133X64C3/512 512MB 133MHz Non-ECC CL3 DIMM
KVR266X64C25/512 512MB 266MHz DDR Non-ECC CL2.5 DIMM
KVR266X64C25/1G 1GB 266MHz DDR Non-ECC CL2.5 DIMM