The change was to "turn off interleaved memory
access". Of course I
only barely know what that means (mostly from just understanding the
component words), but it certainly sounds like a plausible source of
the problem, and a plausible solution to the problem.
Most likely a fairly considerable decrease in sustained memory
bandwidth. How much, I couldn't tell you. But, that's what it is.
--
Nick Reinking -- eschewing obfuscation since 1981 -- Minneapolis, MN