Channel A/B Timing question

For over a year now i've had 990XA-UD3 and 2x4GB sticks of DDR3 ram.

Since their timing was bad(11-11-11-39) i manually set them to 9-9-9-24

since day1. But i set them on Channel A and Channel B. But now i bought

another 1x4GB stick that is the same kind of ram, same kind of timing. I put

it in the 3rd DIMM slot as my mobo manual says, but windows was buggy as

hell, all kind of memory errors. So i went in my mobo settings and set the

Channel B Timing to 10-10-10-24 and now everything is fine. But my question

is, does Channel B Timing control DIMM 3 and 4, and Channel A control 1 and 2?

Because i cant find a ram diagnostic tool that can properly monitor the timing

of each memory, in CPU-Z it says 10-10-10-24 but on Channel A i got it set to

9-9-9-24... how can i know if the 2x4 dual channel sticks are running at cas9 or

cas10?

Channel A/B Timing question