As for your 1:1 FSB:RAM question, while there is a slight gain in performance, it is usually not worth it to keep the RAM clock the same as the FSB clock, because you are only holding the FSB back. For instance, I can run my e6750 at a 1066mhz FSB and my DDR2 RAM at 1066mhz, but it doesn't nearly equal the performance of my FSB at 1600mhz and my DDR2 RAM at 1066mhz.
I'm not exactly sure what you mean when you say it holds the FSB back. The DRAM:FSB ratio is effectively the RAMs multiplier, the main and pretty well only reason why people like the 1:1 ratio is because when you push your processor to extreme levels you don't want to hold your RAM holding you back when you want high clock rates on your processor with tight timings on your RAM.
For example, say your FSB is 400x9 you get a total of 3600MHz or 3.6GHz processor.
In this example your DDR2 RAM would be running at 800MHz at a 1:1 ratio now this leaves alot of room to push the processor higher and/or give your RAM even tighter timings.
However if you had your RAM at a 5:4 ratio your RAM would be running at 1000MHz or 1GHz, which could be two much for many stick of PC-6400 RAM.
On the flip side if you had PC2-8500 RAM then you could push it harder, but most people don't have RAM this high.
So in the case of the PC2-6400 RAM you would be forced to take the 1:1 ratio if you wanted to go to a higher clock rate on your processor while having tight timings and generally speaking tighter timings will translate into better performance then a higher clocked stick of RAM.
On a last note, it has been proven that there are very minute difference where a chipset does favor one multiplier or DRAM:FSB ratio over the other however alot
of work needs to be done and the final result isn't worth the time required to find it.
Edited by james_8970, 30 August 2007 - 10:30 PM.