Question New build not POSTing from time to time due to RAM issue ?

[dn002]

I recently built a new computer and have been having a problem with it every once in a while. The computer runs perfectly 99% of the time. But on two separate occasions since I've built it, it would not POST when I turn the computer on. When this happens, I can see on the motherboard a red LED indicating that the RAM is the issue. Both times I turned the computer off then powered it back on and same thing happens. I then leave it there for like 2-3 minutes and it seemingly "fixes" itself and goes back to POSTing and working like normal. Any ideas why this might be happening?

Just as a side note, and not sure if this is relevant but the very first time I turned on the computer right after putting it together the same thing happened but when I searched I found that sometimes the RAM "needs to train" and just sits there. So I let it sit there while I went to shower and when I came back it posted and worked fine.

Here is the build: https://pcpartpicker.com/list/pfPgxg

 

[Bob.B]

I recently built a new computer and have been having a problem with it every once in a while. The computer runs perfectly 99% of the time. But on two separate occasions since I've built it, it would not post when I turn the computer on. When this happens, I can see on the motherboard a red LED stating that the RAM is the issue. Both times I turned the computer off then powered it back on and same thing happens. I then leave it there for like 2-3 minutes and it seemingly "fixes" itself and goes back to posting and working like normal. Any ideas why this might be happening.

Just as a side note, and not sure if this is relevant but the very first time I turned on the computer right after putting it together the same thing happened but when I searched I found that sometimes the RAM "needs to train" and just sit there. So I let it sit there while I went to shower and when I came back it posted and worked fine.


Here is the build: https://pcpartpicker.com/list/pfPgxg

Turn off expo see if it makes a diff.

 

[Aeacus]

In terms of RAM, download and run memtest86,
link: https://www.memtest86.com/

Guide to install and use it: https://www.memtest86.com/tech_creating-window.html

1 full pass (all 15 tests) is bare minimum. 2 full passes are better while 4 full passes is considered acceptable.

Since it takes a while, best to let it run overnight.
1x 8GB ~1h per 1 full pass. ~4h for 4 full passes.
2x 8GB ~2.5h per 1 full pass. ~10h for 4 full passes.
2x 16GB ~5h per 1 full pass. ~20h for 4 full passes.
2x 32GB ~10h per 1 full pass. ~40h for 4 full passes.

If there are no errors - RAM is sound.
If there are errors - replace the RAM.

For absolute testing of RAM, 32 full passes are needed (due to test #7).
Further reading: https://www.memtest86.com/tech_individual-test-descr.html
But no-one in their right mind is going to do 32 full passes, since it takes forever + then some. Especially when you have a lot of RAM in the system. Consensus in the tech support is that 4 full passes are enough.