the second speed of 100 or 133 mhz in cpu rating is the speed of the bus that goes BETWEEN the memory and the cpu itself. the 450 is how fast things actually occur INSIDE the cpu. the actual circuits that form the pipe between the two is the 100/133. i'll tell you, i have seen a noticeable, if not significant, in going from a celereon 733/100 128meg to a p3 733/133 with 128 meg. but i'm critical and picky, so , perceived result may vary
with a difference in memory size (128vs64) i can't see that there is any advantage to the 133 memory, simply because the clock speed of one-third more than the 128 surely can't make up for the 100% more physically there.