Yes, not sure when they started doing that, but even 386 of the very early nineties had a memory test part of POST. I suspect it started when PC clones came wi

Yes, not sure when they started doing that, but even 386 of the very early nineties had a memory test part of POST. I suspect it started when PC clones came with empty memory slots the users could populate themselves, i.e. the memory configuration wasn't otherwise known in advance. That memory test was however most basic and shouldn't take too long. It was generally insufficient to determine whether memory was reliable.