How to pick the best RAM?

[Vorn]

I'm doing a legacy build using either Phenom X4 9850 (95w) or 9750 (95w), with one of these boards:

GA-MA770-UD3

GA-MA770-DS3P

GA-MA790X-UD4

GA-MA790X-UD4P

GA-MA790FX-DS5

GA-MA790FX-UD5P

So I'm looking over the specs on the Gigabyte site, and each time I see something cryptic, for example, the specs for GA-MA770-DS3P says "Whether 1066MHz memory speed is supported depends on the CPU being used." Question is how do I determine whether or not this board will run 1066MHz with either CPU chosen? I've looked at the specs for the board & compared it to the specs of both CPUs, and everything looks fine. I've looked over the memory support list for this board, and everything looks fine. So why do I get the feeling that I'm missing something? Disclaimers don't appear if there is nothing to disclaim, so I'm worried! Can anyone here explain to this hardware newbie just how to determine if either of these CPUs will support the the fastest memory of each motherboard?

[AtomicMaster]

Motherboards list what memories and memory speeds they support, CPUs have clocks and MICs, which have memory they support, so choose from the center of the venn diagram.

 

The following guide should be helpful too:

http://www.tomshardware.com/reviews/phenom-ii-ddr3,2319.html

[Enthalpy]

Previous processors passed through a northbridge located on the mobo to access the Ram. Back then, the mobo manufacture could tell, from knowing and testing the north bridge it had put, what Ram is acceptable.

 

Your Phenom connect directly to the Ram and they determine the possible Ram. As the mobo manufacturer ignores what Cpu you put, it can't tell what Ram fits. It's your task to fit it with the Cpu you choose.