Possible Duplicate:
Is it better to have 4x2GB or 2x4GB of RAM?
I recently upgraded my iMac (2010) to a 2x4GB RAM configuration and that went well, but I've considering putting the old 2x2GB in as well to get to 12GB. I didn't initially as I've read more modules is usually slower, but the comparison is usually between equal total amounts of RAM (see Is it better to have four times 2 GB or two times 4 GB of RAM?).
What would the performance gains losses look like when comparing 2x4GB and 2x4GB plus 2x2GB in a 2010 iMac? Would the extra 4GB be worth any speed hit?
My usage is generally heavy dev, potentially 2 VMs running inside OS X with Eclipse, XCode, and TextMate open. And TONS of browser tabs (I often reach over 2GB in browser RAM).
(All RAM is same clock speed and timing.)