You should unlock it by doing the L1 trick. Do a google on 'Tbird L1 bridge'. Any stuff you read about 'gaps' is irrelevant on the Tbird as it has no gaps.
Do this and the chip will be unlocked, I.E you can choose any multiplier the Mobo can offer, usually up to about 12.5 on the generation you have.
While you have the chip out to do the L1's, check the stepping of the proc. If it is AXIA then you have a good one. My 1Ghz/100FSB AXIA did 1.54Ghz on air cooling and would post at 1.6Ghz. Check the die itself for these codes. If in doubt, write them all down and ask on here again.
As was said, find your max FSB and when you have hit that, start playing with the multiplier values to see how far it will go. Don't forget that increasing voltage can up the potential maximum clock, but at the expense of a great deal of heat with the Tbird's.
Good luck!
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