Stuck on C5 when installing a memory kit in a brand new Crosshair x870e Hero

[Nacro]

Greetings,

I've been scratching my head over installing a G.Skill Trident Z5 Neo 8000 MHz kit in my new X870E Hero motherboard. When I place one stick in A2 and the other in B2, the motherboard gets stuck with error code C15. However, if I install just one stick in B2, it posts successfully. The same happens with a brand new Corsair Vengeance DDR5 6400 MHz kit—no post unless there's only one stick in B2. I've reset the CMOS, and this is the second X870E Hero board I've tried, both from different stores, with the same issue. Please help! 😖

[Silent_Scone]

Hi @Nacro 

How long are you leaving the system @ Q-Code 15? This is a memory training code. With more than one DIMM inserted, [initial] training may well take up to 3-5 minutes or more. 

[Nacro · Accepted solution]

Thanks, the issue was isolated to dust in the CPU socket