Enabling MEM CLK 2 and 3 ???

[Guest Crusader]

Several times I've seen that people have these two settings Enabled in A64 Tweaker, even when they just use 2 memory sticks.

 

So I wonder, what is this Memory Clock (I assume) setting in A64Tweaker exactly used for? What's its use in overclocking? Does it make the built-in Memory Controller of the CPU stronger/more stable?

 

And does it do any good to Enable them even when using only 2 memory sticks?

 

And lastly, how do I set them to Enabled everytime I restart my computer? (I can't find the corresponding setting in the BIOS to get them Enabled).

 

Thx.