Question PC will only boot with one RAM stick

[xFelipe_G]

Hey everyone,
I just upgraded from a GTX 1070 to a RTX 3070. My system was working perfectly before, but now the PC will only boot normally when either of the sticks is in slot A1. It won't even POST when a stick is in any other slot or when both are in dual channel. I've tried reseating everything and resetting the CMOS, but it didn't work and the problem still persists.

If anyone is able to help me, I'd be really grateful.

Here's the full specs:
Intel i7 7700k, no OC
Asus Z270E Strix motherboard
2x HyperX Savage 8gb 2800MHz
Asus RTX 3070 Dual OC (new GPU) and MSI GTX 1070 Gaming X (old GPU)
EVGA Nex 750G 750w PSU
Corsair MP510 256gb NVMe SSD as boot drive

 

[jojesa]

Does it boot with one stick of RAM on slot A2 (2nd slot from CPU)
Will it boot with one stick of RAM on any slot?
Just to make sure, the RAM modules should be on slots A2 & B2 (2nd & 4th from CPU)
Does the BIOS is up to date?

 

[xFelipe_G]

Does it boot with one stick of RAM on slot A2 (2nd slot from CPU)
Will it boot with one stick of RAM on any slot?
Just to make sure, the RAM modules should be on slots A2 & B2 (2nd & 4th from CPU)
Does the BIOS is up to date?

No. It will only boot when the stick is in slot A1.

Yeah, the BIOS is up to date.

Also, I just got two BSODs: Memory_Management and IRQL not less or equal.

 

[jojesa]

It looks like the RAM modules are ok.
Check the RAM sockets for damage or dust .
Check that there aren't any bent pins on the motherboard CPU socket.

 

[xFelipe_G]

Both the RAM and CPU sockets look fine. I tried booting it up with a single stick in slot A2 and the PC powers up, then it looks like it fails powering up, turns back off and turns on again with no POST. CPU and RAM POST LEDs on the MOBO are alternating between them. When I try to boot it with RAM on slots A2 and B2 that doesn't happen, but still the RAM POST LED remains on.