12.5X Multiplyer on a7v133? How?

[fluxcapacitor]

On my A7V133, I've tried to get a 12.5x multiple w/ BIOS's 1006.01-I, 1005A, 1004, 1003, and 1002.01-A, and they all register it as 13x. Is there a way to get a true 12.5x? The board is a rev 1.05. What I'm trying to do is get my T Bird 1.2 to run 1.5Ghz stable. Earlier today I had it running at 1.5 via several different combinations, but it wasn't totally stable. What I'm now looking at is 12.5x120 for 1.5 w/ the SDRAM clock at 160. I know my chip w/ do 160 at 333, I dont know if it'll like maybe 232 or 332, whatever. But if there's a way to use the 12.5x multiple, please hit me back in this thread...