I have corsair vengeance 1x4gb+1x8gb=12gb.
I just saw people calling this ram number as "weird". And telling me to use either 8gb or 16gb.
Why is that sui?
What is problem with 12GB?
mixing ram sizes your likely forcing the cpu to run in single channel mode instead of dual channel. they can't share memory addresses for anything above the 8gb thats common between the two.
Rules to enable dual-channel mode
To achieve dual-channel mode, the following conditions must be met:
Same memory size (1 GB, 2 GB, 4 GB, etc.)
Matched DIMM configuration in each channel
Matched in symmetrical memory slots
Configurations that do not match the above conditions will revert to single-channel mode. The following conditions do not need to be met:
Same timing specifications
Same speed (MHz)
Memory channel speed is decided by the slowest DIMM module populated in the system.
Maybe it's true for Intel, but on my previous build had 12GB of RAM (2X2 patriots el cheapos + 2X4 corsaire vengence, all DDR-1600 modules) with a AMD Phenom II 955 BE and it was Dual Channel and had no issue whatsoever. Motherboard was a Gigabyte GA-MA790FXT-UD5P.