How to check if RAM is working in dual-channel mode?

Question

A friend of mine arranged three RAM modules of 2GB next to each other on a motherboard that supports dual-channel mode, but is not sure whether it's working. CPU-z shows only a gray area in the memory tab.

Is there a way to check if dual channel is working?

Solution

First, your mainboard must support flex-memory to have dual-channel support for 3 memory modules if it doesn't have triple channel mode

But even if flex-memory is supported then it won't work in dual-channel mode when you install 3 RAM modules with the same size. Have a look at Intel's document, the only way that work is that one module's size must be the sum of the remaining two.

Dual-channel with three DIMMs

Unfortunately it seems AMD doesn't have anything similar to Intel's flex memory

Comments

[phuclv]

Please post a picture of CPU-z and make sure that the 3 DIMMs are recognized correctly

[Frank Thomas]

usually your bios post screen will display information about channel population. Note that many intel chipsets now support Flex/Asymetric mode, where the channels do not need to be matched in chip count or size, but they do not operate as optimally in that configuration as they do in symetric dual/tri/quad channel.

[Ramhound]

If he has only 3 modules then at least one channel won't be in dual-channel mode

[programstinator]

Thanks for answering, but some things are still unclear, since we are using an APU a8 (AMD) processor, and you're using Intel as a reference. Does this matter at all? Also, there is no indication in BIOS, apart from the amount of memory (6 GB). Also, CPU-Z didn't show the dual channel feature working even when we removed the third DIMM. I've convinced my friend to make an account. He'll post imgur screenshots later on.

[phuclv]

Sorry but you hadn't mentioned AMD before. And I don't think AMd has flex memory feature like Intel