On first glance, it may seem like we target nocona, which is an architecture type that dates back to 2004. However, we have a default-enabled "experimental optimization" that brings us up to sandybridge.

So, in reality, our x86 default targeted architecture has been has been sandybridge since v5.0.

This review is just to remove that experimental optimization and encode the sandybridge target in the defaults. To be clear, this change just makes already-existing behavior more obvious, and there will be no behavior changes in builds after this ticket is completed.