X2 4400+ Core 1 Errors when Benching Core 0

[Theta]

I'm testing out a new 4400+ we got in today, and having some strange problems with it.

Right now, at 1.7v and 2800, Core 0 is stable as can be. Core 1 is fairly unstable at 2800. So, backing down to 2700 @ 1.7v, both cores seem rock solid.

However, I can only test Core 1 WITHOUT testing Core 0. As soon as I test Core 0 at the same time, POOF - error on Core 1. This seems to be more than a coincidence.

Anyone seen this, or am I just nuts?

BTW - 1.7v to not even hit 2800 on a 4400+ Toledo seems like a DOG...