PC2 6400 posting as 4300 when system overclocked?

[pchoi04]

I'm running the Corsair TWIN2X2048-6400C4 and when my BIOS is set to default on the post screen it lists my system specs and everything looks fine. But when I start overclocking and tweaking my memory and such its posting as PC2 4300... Why is that? Am I doing something wrong?

 

[TurdBurglar]

It depends on if you are leaving any RAM options in the BIOS on auto

 

[pchoi04]

Whats the first step I should take to make it read properly?

I have a P5B Deluxe.