Windows 7 ultimate
EVGA LGA 1366 Intel ATX X58 SLI LE
I'm using the system for sound/video production, with a good bit of gaming on the side. I'm basically wondering if the 12gb set would be limited by the 6gb set. A friend brought up the issue of cache sizes but the technical details were a bit above my current understanding of computer hardware. Any thoughts?
If you go to the Corsair support forum and ask the question, they will certainly say that they do not recommend it.
Adding ram afterward is not guaranteed to succeed, even if it is the same part #. Internal characteristics can vary considerably, and some motherboards are sensitive to the differences.
That is why ram is sold in kits.
It might work, and you would operate at the lowest common denominator of specs, and at the same voltage.
I suggest you get a single kit of the size you want, and market your old ram.