Too much RAM?

Reading comments in a discussion I came across these comments from Chas;
That said, I suspect that the root cause of your bad CDs is too much RAM.

There is a known W98 bug if 512MB or more RAM is installed. I limit ALL of my W9X boxes to 384MB.

The ‘bug’ is VERY configuration dependant. Anything from new hardware to an updated driver can trigger the bug.

Try removing some RAM and burning a new CD to see if that corrects the bad burn issue.

and it could explain some problems I’m having.
The question is this, why [briefly] does this happen and will changing the OS allow me to boost the RAM above 512?
Also, am I being thick, how does he limit W9x boxes?
tia Pete