Can't get dual-channel memory status from Linux -- why?

Try this:

dmidecode -t 17 |grep Channel

For dual channel, you should see your channels A/B as:

Locator: ChannelA-DIMM0
Locator: ChannelA-DIMM1
Locator: ChannelB-DIMM0
Locator: ChannelB-DIMM1

We saw many response, in many places as we have the same question. There is some debate about the dmidecode output, as if it show the location, but does not state that a specific slot is working with a combined bandwidth.

If you do populate your motherboard with ram sticks that are incompatible for dual channel config, it will still show the same locator, but will not combine the bandwidth.

For Windows, many apps show if it is in dual, triple or quad channel mode; while for linux, we had a hard time to find any.

on the other hand, the old-school and yeat very effective memtest86+ will show the memory access bandwidth - 64, 128, 196, 256bits for single, dual, triple and quad channel respectively.

In the image bellow we have a triple-channel capable motherboard, that is running in the triple-channel mode.