Here are the specifications concerning your question about your motherboard's RAM.
Number of Memory Slots
4 x 184 Pin DIMMs
Supported RAM speeds
400 MHz • 333 MHz
Max Supported RAM
The key factors that are the most important when you select your ram is the MEMORY TYPE DDR SDRAM, 184 PIN DIMMs, and the SUPPORTED RAM SPEEDS 400 MHz and 333MHz. Your motherboard will support memory no more than 4 GB of memory, so yes you could use the 128mb modules, but you must make certain that they are DDR SDRAM types and 184 Pin DIMMs as this is what the manufacturer suggests is compatiable with your specific motherboard. The supported speed is also a suggestion, because this is the max speed that will work at it's optimal level. You can buy some ram modules that are higher, but they will clock down to the max speed allowed by your system. In other words, say for example you went to your local best buy or circuit city and bought the suggested memory type with the proper pin count and DIMM modules but they only had 500 MHz bus speed, then your system would clock the speed down to 400 MHz. With 4 128mb modules you are only going to get 512 mb max memory, because 4 x 128 mb = 512 mb so you will not be using all the available memory capacity that your motherboard can handle. If you wanted to maximize your memory usage you could buy 4 of the 1 GB memory modules or buy 2 of the 2 GB modules to obtain your max capacity. In your case buying 4 128 mb memory modules would not be worth it because you could buy 1 of the 2 GB modules and get better memory usage.
Another important thing to remember is that you should always use the same type of memory modules and never mix and match them with different ones as this could cause system crashes and problems with lots of memory errors. When going to a local store and asking a sales rep for compatible ram they will ask you what is the make and model of your computer and what your processor speed is because your processor speed also determines your bus speed because your ram will not operate above that speed it will simply clock down (if it is rated higher than what your processor speed is), with this information they will look up any compatible ram they may have in stock. Hope this answers your question and if you need further assistance please let me know.
p.s. your motherboard can support up to a pentium 4 class processor, but this may be different than what you have in your system.
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