AMD Thunderbird & Duron Overclocking Revealed

It turns out that pins AN27, AL27, AN25 and AL25 correspond to BP_FID pins 0 – 3 and guess where they are physically located on the CPU in relation to our four ‘OVERRIDE’ jumpers? 

You guessed it, they’re right next to our precious jumpers, so there’s one point in support of the theory that FIC’s ‘OVERRIDE’ jumpers are actually controlling the BP_FID pins and not the FID pins as we originally thought.

Why couldn’t we figure out that these pins were the BP_FID pins earlier?  These four pins are actually listed as NC in the Thunderbird/Duron documentation, NC meaning “not connected.”  And normally, if a pin is listed as NC there would be no reason to assume that the docs are lying and it is actually connected.  But as John C. managed to find out, the pins are actually connected and are actually the four BP_FID pins we were looking for. 

Keep in the back of your head the point that these four pins are listed as NC because that could affect the future overclockability of Thunderbirds/Durons, which we will discuss later, but now back to this theory.