GIGABYTE X470 AORUS ULTRA GAMING
Corsair Vengeance RGB Pro 64GB (4x16GB)
2080 Super Founders Edition
WD_Black SN750 500GB NVMe
BIOS version "F50"
Ryzen 7 3800X
Windows 10 pro
I was using the 2700x before and there was no problem using the 4 slots with 64 ram, when I changed the processor to the 3800x the PC would not turn on if I used 4 slots only if i left 2 slots.
First Gigabyte boards are known for having this issue with 4 slots and Zen2. Lots of complaints on this. I would report the issue to Gigabyte and see what they have to say. Not sure why this is, I only know I have seen what I would consider to be an unusual amount of their boards with this issue. This has been said by several tech sites too.
Also did you use memory that was on the QVL list for your board and the 2700X?
Also did you verify that the memory was on the QVL list with the current bios revision and the 3800x.
Lots of QVL lists change when the processors change.
You can also make sure the timings are being set properly. Just because they were with the old bios and processor doesn't mean they still are. You can ask your ram maker what timings you should use and set them manually if need be.
Make sure to test with XMP off too. This will be less aggressive on the ram and you can see if it makes a change. You may have already tried this?
Make sure the board is at bios defaults too with no overclocking and PBO off. See if that helps.
You may need to boot 2 with just the 2 sticks to make these changes then add the sticks back in to see if it helps.
Don't assume it is just 2 sticks work and that it is not the sticks themselves that are the problem. When it boots with 2 sticks, turn it off and remove those 2 sticks and put the other 2 sticks in their same place as the ones that worked and see if it works. If not you could just have a memory stick issue.
I will link to the correct QVL Lists for you in the next reply post.
Since I don't know your memory module part number I can't look it up for you.
This is the link to the QVL list for the 3xxx or Matisse processor series: https://download.gigabyte.com/FileList/Memory/mb_memory_x470-aorus-ultra-gaming_matisse_190828.pdf
This was for the 2xxx or Pinnacle Ridge processor series:
this is the QVL list https://pangoly.com/en/review/gigabyte-x470-aorus-ultra-gaming/compatibility/ram I did not check if the QVL list with the bios f50 has changed
I already tested each stick and they work fine now I'm going to try to disable XMP and I don't have OC
Forgive me if I missed but if your ram is what is highlighted above, I did not find it on the QVL list for either cpu at Gigabyte. Not sure where the site you reference go their info. I gave the link to the two correct QVL lists and don't see that part number on there. Again sorry if if is there and I somehow missed it.
Again this doesn't mean that with the right manual setting it won't work, so look into that.
You can certainly try different ram. I would buy it retail locally so you can return if it does not work out. Hate to say this but you could also get another board.
If you think there is a chance you will want to upgrade later to Zen3 a B550 may be a good investment. I would if I could buy anything you can locally so you can return easily if need be.