still data corruption with 5.1-R on Intel Pentium 4

There have been threads about data corruption in RAM on P4 and other
i386 machines on this list.  I also observed the problem, on my laptop
with 5.0-R.  It seemed to go away with 5.1-R, on the laptop.

Recently I upgraded my home PC which is a P4 2.0A from 4.8-R to 5.1-R. 
No problems at first.

Until I ran "portsdb -Uu".  I got a couple mysterious SIG4 and SIG11.
Just to be sure I rebooted and tried again, same result.  I rebooted
another time, this time with ACPI disabled, and tried again, still the
same.

Then I rebuilt my kernel with options DISABLE_PSE and DISABLE_PG_G, as
suggested by Terry in the old threads: Bingo, everything is fine now, no
more SIG4 or SIG11 during portsdb -Uu.

It seems the workarounds that we have in 5.1-R are not effective enough.
What do you think?

--
Regards,
Georg.