RAM bandwith operation


Nov 30, 2007
After some research on the forum, I decided to post my question regarding the RAM's bandwith VS the CPU's bandwith.
I need to build a virtual computer for a school work and my teacher, wich is never really sure of what he says, showed us how to save on money by choosing the right RAM frequency. The fact is that Im not sure if this special operation is the right thing to do before buying RAM since no one really seems to talk about this.
Here is the example of my build,
The CPU I chose is the Intel Core 2 Quad Q6600 with 1066 FSB
To know what's the bandwith of the CPU I have to do this operation :

64 bytes bus/8 bytes * 2,4 GHz (frequency) = 8528 Mb/s (CPU's bandwith)

Then, I need to know if the RAM's bandwith will not create a bottleneck :

64 / 8 * 667 MHz * 2 (dual-channel) = 10 672 Mb/s (RAM's bandwith)

So, the 667's bandwith (10 672 MB/s) is enough to sustain the CPU's bandwith. The 800 would be good too but, considering what I learned, it wouldn't do a better work than the 667 and would cost a little more.
That's why I chose 667 RAM considering that it will have the same performance that a 800 would have on my system.

BUT, my question is : Is it the good thing to do (the operation) to choose the best RAM I need ? Are there any other factors that should modify my choice ?

Tell me if there's anything unclear. I did my best to explain it in english (im french).

Thank you.



Apr 20, 2004
I've heard that tighter timings were more important. ie 4-4-4-4 would be worse than 2-2-2-2. I don't remember if that applies to everything or just to gaming ( or it might have been that you could over clock the memory speed with some modern M/B. )

I personally don't think it is that important. :hello: