Intel Pentium D processors 840, 830, 820 will undergo the following changes
for the A-0 to the B-0 core processor stepping change :

CPUID will change from F44 to F47
B-0 is pin compatible with A-0
New S-Specs for converting products

Most of the planned fixes are surrounding Intel EM64T. There are two more
errata added mainly addressing the FSB issues.

 Intel Pentium D B 0 Stepping Info

Intel Pentium D processors 840, 830, 820 will undergo the following changes
for the A-0 to the B-0 core processor stepping change :

CPUID will change from F44 to F47
B-0 is pin compatible with A-0
New S-Specs for converting products

Most of the planned fixes are surrounding Intel EM64T. There are two more
errata added mainly addressing the FSB issues.