Got a question from my brother and I'm having a hard time finding an answer to this specific question.
My brother has a Haswell i5 and a Gigabyte Z97MX-Gaming5. One kit of G.Skill 2x4GB DDR3-2133 and one kit G.Skill 2x8GB DDR3-1866.
He was having some issues over the weekend where his PC wouldn't even hardly post. Long story short, it seems that a BIOS flash did the trick (not sure why). In the meantime we got to discussing his RAM speeds/timings/voltages (since I was convinced RAM was the source of his problems). I told him he could probably run them all at 1866MHz CAS 9 @ 1.6V and be ok. But he noticed a setting in his BIOS where it seemed he could set different speeds for each bank (A slots and B slots). I've never heard of this.
Is it possible to run each kit at different speeds?