What does A0 stepping mean?

[Viktor_4]

I found an ad where smbd selling Intel Xeon E5 Haswell-EP 10 cores 2GHz LGA2011-3 cpu with notice that its going to be hard to find motherboard for it becouse of A0 QDD1 stepping. Is it true?

 

[DonkeyOatie]

QDD1 is a specification for that CPU. A0 stepping means that it is a first-first run, so it is an Engineering Sample, and there may have been (very likely) microcode or other changes before final production.

Stepping refers to enhancements and revisions in design and manufacturing of CPUs.

I don't know the issues specifically, but there may be a challenge finding a motherboard with a compatible BIOS version.