Excited about Intel's Ivy Bridge baked in PCI-E 3.0 Support? Check your stepping

[caveman-jim]

A forum post at Anandtech has shed some light on the apparent issues Intel's new Ivy Sandy Bridge E processors have with running multi-GPU configurations with the built in PCI-Express 3.0 controller:

Update from ASUS: Just asked HQ, they told me some CPUs can't handle two cards in Gen 3 mode. Intel know about this and won't chage out the CPUs. Apparently the C2s are better than the C1 steppings but Intel have now removed official Gen 3 support from their product pages. If that is the issue, what you can do is set PCIe to Gen 2 mode in UEFI just to debug and see if the lock ups persist. If they do then the issue lies elsewhere, if they do, then the CPU is not capable of Gen 3 on two slots at the same time. Some CPUs are better than others in this regard and it is luck of the draw.

If you're jumping into Sandy Bridge E for more bandwidth under your multi-GPU configuration, double check that stepping code - you might be falling back to PCI-E 2.0 speeds to avoid hard locks.

Thanks for forum member demo for the info.

Note = the original issue here is reported on Sandy Bridge E platforms, not IB. No idea if there's anything wrong with IB.