2nd RAM slot not working

[oshin]

I recently bought a 2nd ram stick, but whenever I tried to install it in my computer, the troubleshoot light switches between CPU and DRAM
I have already tried updating BIOS, enabled XMP, the one I bought works fine when in the 1st slot, but if the original one or the new one go in the second slot my PC wont boot.

 

[HamBown81]

Is this only a problem when the sticks are together. Quite often, unmatched DIMMs will have compatibility issues.

What motherboard and CPU?
What exact RAM?
Are both sticks exactly the same?

 

[DRagor]

Two possible causes:
- bad ram slot - have you tested 2nd slot with nothing in first slot? If yes, and that won't work, it means you have faulty slot on motherboard (or bent pins at CPU socket)
- old stick will not work with new one - happens when you try to mix sticks not from same kit.

 

[oshin]

MOBO is MSI H110-M
Processor is i3-6100 3.7ghz
Both sticks are Crucial Ballistix Sport DDR4 2400mhz, but arent exactly the same.

 

[HamBown81]

As DRagor suggested, if the sticks both work on their own in each of the slots but do not work together it is likely a compatibility issue.

Otherwise you could possibly 1)have a bad slot 2)CPU socket damage

 

[oshin]

So, they both work, but only in the first slot, neither of them will work in either configuration when in both the slots, nor will any work in the 2nd slot by itself.

 

[HamBown81]

So, they both work, but only in the first slot, neither of them will work in either configuration when in both the slots, nor will any work in the 2nd slot by itself.

Try removing the CPU and inspect the socket for bent or broken pins.

 

[geofelt]

I had a similar situation.
To test, we put both sticks in my motherboard and both worked.
I put my cpu in his motherboard, and both worked.
I put his cpu in my motherboard and only one stick worked.

The conclusion was that there was a minor defect in the cpu that did not recognize a second channel.
Under warranty, the cpu was returned to intel and replaced.
On reinstallation in his motherboard, all was well.

We were fortunate to have a second set of compatible parts to test with.
Also, we were fortunate that the 4690K was barely still under warranty.

The s-spec id will tell the date for warranty purposes.

Really though, the likely culprit is a bent pin in the motherboard socket.