I've taken some time to do some more testing on this. I've reloaded 7264 x64 as a clean install dual-boot so here's the testbed:
Lenovo X61t tablet notebook:
7232 x64 (upgraded full app complement)
7264 x64 (clean install vanilla)
Core i7 920 workstation:
7232 x64 (clean install full app complement)
7260 x86 (clean install vanilla)
normal and overclocked hardware
I used a 23GB backup image file to copy between systems.
Observed symptom: when copying the file from one system to another over Gigabit LAN the target system completely freezes, requiring hard reset.
Test result: The only time I encountered the freeze (always REPEATABLE, with varying timing) was when copying from the notebook 7264 to the OVERCLOCKED workstation 7232, not if running at normal speeds. All other combos where OK, including overclocked.
Conclusion: this particular problem is in 7260, and is exacerbated by the target being on the ragged edge of execution.
Notice that only the system with a full complement of applications installed and many background processes froze, and then only when overclocked. It just so happened this was my initial 7264 environment configuration since my workstation is overclocked as the norm.
Also of note is that the problem is not an overclocking failure, but a hard system deadlock. The overclocking just seems to egg it out
BTW, the overclocking configuration can handle over 2 hours of 100% CPU, cache & memory stressing without failure, but obviously there's no networking going on there.
It appears this problem is introducing some kind of system deadlock under certain circumstances which are more likely under system stress. So chances are most people will not encounter this.