I just bought a 5900x, MAG x570 tomahawk and G.skill F4-3600C16Q-64GTZNC (4x 16gb). I built the pc turned on the XMP and ran memtest86, just to be sure. And surely the memtest86 throws a single error. I proceed to test the ram with only two sticks, placed them the 2nd and 4th slot, turned on XMP and ran the memtest86. All four sticks passed the test. I did the same test for RAM slot 1 and 3 and the system won't even post if I enable the XMP. Three beeps for the memory error. I tried raising memory voltage to 1.4 and still nothing. Only when I decrease RAM speed to 3200 will the system posts with XMP. So I placed all 4 sticks of RAM back in the system. The PC will turn on but won't post, unless I turn it off and wait couple of min? After a few min it posts and even if I turn on XMP with all RAM installed, it boots normally. The MOBO is running latest beta BIOS. The RAM isn't on a QVL on the MSI website but is on G.skill website. Honestly, I have no idea what could be the problem. Could there be a problem with a weak IMC, incompatible memory or even an issue with MOBO? And kind of help or guidance will be greatly appreciated.