My friend has a Mercury PVCLE266M-L mobo based system. [CPU VIA C3 Samual 2 processor onboard FSB 133MHz Chipset CLE266/8235] The mobo's specification/manual tells it supports DDR266 i.e: "Memory - 2 x 184-pin DIMM sockets support two2.5V DDR SDRAMs (DDR266) - Maximum: 2GB " One fine morning his single stick memory (DDR266, 256 MB) failed. After that he installed a DDR400 stick which worked well. My questions are : (1)" Is it advisable to use DDR400 or DDR333 on this board when the specification says it supports only DDR266 ?" (2) " Is there any adverse/+ve effect if we use DDR400/DDR333 on this board? "