Gigabyte X79 UP4 memory channel issue

[Fazeel Raza]

Hi, guys.
I have a weird issue, searched for it over the internet but can't find anything similar. Back in the days I was using a 24GB RAM, one is 16GB corsair dominator platinum 2400mhz kit and another one is corsair vengeance pro 8GB 1866mhz. I was running both at 2133 mhz. not to overload anything.
The configuration of RAM in channels was as follows
Channel A : 8GB - N/a
Channel B : 4GB - N/a
Channel C : 4GB - N.a
Channel D : 8GB - N/a
But the issue I am having is that my system now doesn't recognize the RAM in channel B.

It counts that memory to be 24 GB but for system it shows 20 GB. I detects and says that 4 GB DIMM is installed but doesn't include it in system memory.
The last change I did to the system was Water cooling CPU and GPUs.
My specs are as follows:
Core i7 3930k
Gigabyte X79 UP4
24 GB RAM
2x GTX TITANs
Corsair AX1200 PSU.
Also note that I never overclocked anything and that all the stuff is running at stock clocks.
Please help me. Thank you!

Also, I checked my RAMs. as the RAM that was used in channel B works in other memory channels, which means it is fine.

 

[joex444]

Did you try a different memory stick in Channel B? It could be that slot is bad.

Also, you are not running things at stock. You have 1866MHz RAM in Channels B and C running at 2133MHz; the other memory is within spec as it's rated for 2400MHz and can run 2133MHz without problems.

Ideally you would have four of these 8GB modules and be running them at some speed up to 2400MHz. I'm not familiar enough with X79 configs, but either this setup *should* run 16GB at quad channel and 8GB at dual channel (or perhaps single channel), or the whole thing reverts to some lower speed. With four 8GB modules it would unambiguously be 32GB in quad channel.

 

[Fazeel Raza]

Did you try a different memory stick in Channel B? It could be that slot is bad.

Also, you are not running things at stock. You have 1866MHz RAM in Channels B and C running at 2133MHz; the other memory is within spec as it's rated for 2400MHz and can run 2133MHz without problems.

Ideally you would have four of these 8GB modules and be running them at some speed up to 2400MHz. I'm not familiar enough with X79 configs, but either this setup *should* run 16GB at quad channel and 8GB at dual channel (or perhaps single channel), or the whole thing reverts to some lower speed. With four 8GB modules it would unambiguously be 32GB in quad channel.

Yes, I placed dominator RAM in channel B, but no success. :/