i have been looking at an upgrade for my pc and i find it have hard to work out all the figures ram has to describe it. i understand the mhz speeds but what difference do timings mean, for instance is 5-5-5-10 good? and also whats does the pc2100/3000 or whatever mean and last but not least whats does ddr266 or ddr 333 mean? i know what ddr stands for but i have no idea about the rest. thanks in advance for any information.