user: Question: What is the Southbridge when the CPU support was Athlon, AthlonXP, Duron( SocketA ), Alpha21264?
Columns: ['Model', 'Code name', 'CPU support', 'FSB / HT (MHz)', 'Southbridge']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['AMD-640 chipset', 'AMD-640', 'K6 , Cyrix 6x86', '66 (FSB)', 'AMD-645']
SQL:

assistant: SELECT "Southbridge" FROM "Table" WHERE "CPU support" = 'Athlon, AthlonXP, Duron( SocketA ), Alpha21264';