DDR2-1066 4GB Ram Stick Mixed with 800MHz, or mixing Ram in General????

[Pedro Sanchez IV]

Gigabyte GA-EP45-UD3P motherboard. I already have Crucial 4GB Module
DDR-2-1066 speed. I need to know if it's possible to mix in a 2GB or
4GB DDR2 but with a LOWER speed like 667 800 or other's?

The ram I have is the DDR2-1066 4GB Made by G.Skill

Thanks!

[kony]

When you drop in lower spec'd parts, if the bios works
properly, it drops the whole bus down to the lowest common
denominator, the slowest memory in the system.

You didn't mention the CPU, that is what determines the FSB
speed and corresponding memory bus ratio.

Generally speaking, yes what you want to do is "often"
possible, but memory is dirt cheap today, why would you want
to potentially cripple a system instead of giving it the
highest memory bandwidth possible?

I know, it is because you already have the memory, right?
IN that case, the choice is simple, benchmark it before and
after then decide if the change is worth the cost savings to
you.