Do you have an older 430VX or 430TX chipset motherboard? IIRC these two chipsets could only cache the first 64MB of memory. So if you had more then 64MB your computer might actually be slower ...
DIMM and SIMM are two major types of random-access memory standards for personal computers. DIMM is an acronym for "dual in-line memory module," while SIMM stands for "single in-line memory module." ...