F4-2400C15Q-32GRK Fails to Boot w/ XMP on GA-X99-UD3P

[FourOh]

I am unable to boot to Windows with XMP profile activated, even with voltage bumped to 1.25V. Appears to run fine at stock 2133 speed.

This RAM was listed on Gigabyte's QVL and listed under G.Skill's RAM Configurator.

i7-5820k at stock speed
GA-X99-UD3P
F4-2400C15Q-32GRK

[GSKILL TECH]

Do you have the latest BIOS?

Test one module at a time to see if each can pass

[SakuraIchigo]

I have done that and neither passed

[FourOh]

I tested each stick individually with XMP Profile enabled - all passed MemTest86 testing and booted to Windows 10. Once in Windows, each was tested with Prime95 for stability. Each stick was able to pass these tests. However, when in pairs or the set of four, I am unable to boot with XMP profile.

This set was intended to replace a set of F4-3200C16D-16GVK, which functions well at XMP.

Please advise-

[GSKILL TECH]

So assuming you have the latest BIOS, may be best to send them in for RMA exchange to see if a new kit works better.

Any two modules will not work at 2400?

This is a very strange problem.

[FourOh]

Bios is latest, F21a. Testing four sticks in a variety of combinations is time consuming, but I will try a couple more configurations before proceeding. Yes, it is odd given the fact that the 2x8gb DDR4-3200 works quite well.