Many thanks for answer my questions.
But now I'm really confused - Celeron G1610T is in the Intel ARK as supporting ECC memory -are you saying it doesn't?
What is the position with the officially supported i3-3240 variant? HPE sell this variant of the gen8 microserver with ECC RAM. So have they tweaked the BIOS to support/recognise the i3-3240 and work with ECC RAM in a system that is not actually activating ECC function?
The i3-3240 indeed does not support ECC, we can't help it. We are at the mercy of what Intel has available.
You have to understand that unless this is a mission-critical server, ECC won't do much for you. If you truly want this feature and good performance, then as I said before, just get the supported Xeon E3-1220Lv2.
If you want the higher clock speed, then go for the i3-3240. You will not have ECC enabled but the system will be faster. ECC being enabled is slower than having it disabled anyway.
Here's the quickspec sheet in case you need it: