if im not mistaken,the ram's higher clock speed will benefit much more on P4 platforms than tighter timings.there was an article on this that i read, that showed quite a significant difference in SiSoft memory benchmark.but that article was published before the days of the A64..

for me, i can see that higher ram clock speed is better that tighter timings because my rams are not capable of 2-2-2-5 at higher clocks.IIRC, my rams can take 2-2-2-5 only till DDR410.i did a superpi comparison with the rams at DDR410/2-2-2-5  with DDR500/2.5-4-3-5, and the second setting gave better results (cpu speed was kept the same).