It depends which prime you are running.

I was with Orthos beta the newest version and so far just 20 minutes stable at 9 X 400 = 3.600 E6600 after many errors appearing, I could not pass of 20 minutes. So I changed the version to SP2004 and so far 4 hours stable. I have to say trying beta versions is no way good, if you are speaking about stability.

Is the same if you test memtest86 for ms-dos or memtest for windows. We cannot compare, Ms-dos version all the way, it shows true erros.

I'm testing the beast as it has to be tested