i think he means one is sdram, and one is ddr sdram. theyre both sdram, however. one suggestion would be to change your theme. in the display settings, change it to windows classic: its a lot less ram intensive. and no, if you have pc 100 in there right now, you can not hold pc3200. the ram you have right now is 168-pin ram, while pc3200 will be 184-pin. my suggestion would be to get a new setup entirely, sdram is expensive, seeing as to how it is no longer mainstream.