What if I overclock my ram when i have 2 different types?

[mmcato]

I have 2 different brands of ram in my system, which importantly have 2 very different clock speeds. One is about 600 mhz lower than the other, and of course your pc defaults to the lowest clock speed for your ram. I unplugged my two sticks that are low clock speed and then overclocked my good RAM to the highest stable overclock it can handle. The issue that I have now run into is that 16gb is literally right on the verge of not enough RAM for the game I am trying to play, but the overclock has made a severe difference in the frame rate. Almost a 30 fps difference. I know, crazy, but its true. If I plug the other sticks back in, and keep the current clock rate of my RAM, what will happen? If I can not have the RAM clocked to that rate with the other sticks in, is there a way to overclock RAM on a per slot basis? I have the ASUS EUFI bios. Thanks guys I know this question makes me look like im an idiot but id like to save the 60 dollars if i can.