text: what kind of ram can i update my ibm r40 model 2681-hu1with?   your ibm thinkpad r40 model 2681 need ddr pc2700 • cl=2.5 • unbuffered • non-ecc • ddr333, maximum is 2 modules of 512mb. http://www.crucial.com/store/listparts.asp?mfr%2bproductline=ibm%2bthinkpad&mfr=ibm&tabid=am&model=thinkpad+r40+series+%28type+2681%29&submit=go