The L2 bridge controls the amount of cache that the CPU has. Some CPUs, such as
the Applebred Duron and the Thorton Athlon XP have more cache on the die than
what is enabled. In some cases, this extra cache was disabled as it was tested
and was defective, but in other cases this extra cache is not defective and can
be re-enabled safely (though may require a higher than normal vcore).
Since there are multiple configurations for the same cache size, it is thought
that different configurations use different parts of the cache. So if one bridge
configuration does not result in a stable CPU, then using a different one with
the same total L2 size may result in a stable CPU.
The bridges can be rejoined or the cuts can be filled with a conductive
material. Rejoining is recommended as removing the conductive material can be
difficult if the cache turns out not to be fully functional.