RAM Channel B on motherboard not working

[DaaveRaave]

I have a Slimline 450-a114. It has a Memphis2-S motherboard that originally had BIOS revision NUT version A0-08. Today I upgraded it to version 10 (dated 1/5/2016), which appears to be the latest version.

The PC originally came with one stick of 4 GB RAM, installed into Channel A.

Since I need to use Chrome with many tabs open for my job (which is for the time being, working from home), I determined I needed double the amount of RAM, so I used the Crucial memory configurator and correctly determined I needed product # CT51264BF160B, which I purchased and installed.

After not being able to boot correctly, I eventually realized that only Channel A on the motherboard works. That is, I can successfully boot with either the original stick or the new stick in Channel A. The moment I put either one in Channel B, regardless of whether or not Channel A is empty or filled, the PC won't boot.

So I figure there is either a hardware or software problem. if the former, I figure it's not worth correcting.

But I wonder if there may be a setting in the BIOS or maybe a motherboard pin setting I need to know about to make this work? That is, if this is a software issue, does anyone know how I can get Channel B in the motherboard to work?

Thanks in advance.

[wb2001]

@DaaveRaave

You did an excellent analysis. Swapping out the modules in channel A was a plus. The minor speed difference is not a problem, the next module would slow down to match the old module (if both has worked together).

Remove the power cord, and then open the side panel.  With a can of compressed air, blow out the RAM slot.

[DaaveRaave]

No such luck! I will assume this a hardware problem.

Thanks anyway for the suggestion.

[wb2001]

@DaaveRaave 

The last check I can offer would be to inspect the slot with a magnifier and pen light. Some have reported bent pins caused during the insertion of the RAM module.