they can't be exact same make and model with that ram capacity in a dual channel mobo. Some of the sticks have to be different capacity and that breaks the same make and model barrier. Same make yes but model would be different at the least, even if just slightly due to capacity assuming CL/CMD rate are identical. Point being this still can have performance issues. I am assuming you have something like 4 sticks...2x4GB and 2x2GB if I had to guess. If so try uninstalling the 2x2GB or what ever the lower capacity ram is and then see if your frame rates are better or if you're still having issues. Do that and let me know how it goes. I'll help you trouble shoot it from there.