I have a f.siemens with a D1740 board. I have had this for 4 years, it only had 256 of ram when it was new,after a year I bought an extra 512 from crucial using their on line selection, computer works fine. Just downloaded CPU-Z and found that the original 256 is PC2700 and the one crucial sold me is PC2100. Its a bit late to complain now but I am wondering what impact this is having on my system, and what is the best thing to do considering the sky high price of this type of memory, Bill