John Doe wrote:
Right... Even if the unlocked CPU will probably function normally,
the idea that the other cores might be defective puts doubt in the
idea of unlocking the thing. Unless it can be re-locked?

As far as I know, it is just a BIOS trick. I did manage to find
some web articles, which suggest there is an electrical signal
running from the Southbridge to the processor, and there is some
kind of communication. But so far, I haven't found any details
as to exactly what they send from the Southbridge to the processor.
In any case, the "unlock" would be a process that happens on
each BIOS POST. Turning ACC off in the BIOS, should stop the
unlock on the next reboot.

There is a picture of the BIOS screen here.

http://images.anandtech.com/reviews/...llowup/ACC.jpg

Another thing I didn't know, is the ATI SB750 Southbridge, has its
own processor inside. There is an 8051 inside, and the ACC function
is somehow associated with that block. But the details aren't in the
documentation, as to what they do with it. Intel has a similar
scheme, but it is for IT control of computers in large corporations
(AMT). I don't get the impression the 8051 inside the SB750 is
quite that ambitious. It may be used to control fans or something,
or replace part of the functions of the SuperI/O chip. That is all I
could find. The "EC" in the BIOS screen, stands for "Embedded Controller".
The AMD documentation refers to IMC or Integrated Micro Controller.

Paul