ecc mode in memory testing

[adler-wRvlPVLobi1/31tCrMuHxg at public.gmane.org (Stephen Adler)]

I'm running the memx86 memory tester on my system which has ecc memory. 
Should I test it with the ECC mode on or off? I can think of reasons why 
I would test it with the ECC mode on or off, but I don't now which is 
the most standard way of testing memory.
(if I turn on ECC, this could potentially hid marginal memory, thus I 
want it off. On the other hand, if I want to test to see if the ECC is 
working, I want to have it on during the test..)

Cheers. Steve.