It's given a false negative once before on an Oktagon SCSI card, but I guess that isn't an isolated case. Maybe it's seeing non-RAM areas as RAM?
Your system can work properly, (without crashes, strange things) even some bit errors exists. If all memory seems to be bad, then possible the test prg is wrong, or socket contacts, or the controller is faulty. In this case Your system should be hard crashes, hangs allways.
Check memory timings. If ok, and all works fine, i bet: the test prg.
