Panic with 2 quad opterons (2346)

[Ken Mandelberg <km@mathcs.emory.edu>]

I've been trying to upgrade a box that had two dual opteron, to two quad 
opterons (2346). The motherboard and firmware is documented as 
supporting this.

I've tried the latest Ubuntu and Centos distributions.

With 32 bit  kernels, the two quad cores work fine.

With 64 bit kernels, and only one quad core inserted it works fine.

With both quad cores, the 64 bit kernels panic immediately.

In all tests there are 4 2GB dimms , 2 in each in bank.

Any thoughts?

Please cc me directly on any response.

Thanks!