- Jul 8, 2003
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So I got my new Inspiron 9400, and accordingly - thought it would be a good idea to try to clock it up (to see if it could even be done). The datasheet for the Pentium Duo states that BSEL[2:0] is a 3 bit bus which selects the FSB clock speed (or rather, is queried by the 945 chipset to determine the bus speed). So I figured no problem, for a quad pumped 133 Mhz, BSEL[1] is low, while for 166, BSEL[1] should be high. Therefore, cutting pin BSEL[1] and causing it will float will cause the internal pullup on the 945 to read a 1, in theory giving me 166FSB.
Unfortunately, it seems that Intel implemented some new tricks in this series of CPUs. It detects the change, but drops my FSB down to 100Mhz. I'm guessing that the new chipsets also query the processor ID to determine the maximum operating frequency. I was able to restore my processor by tying together BSEL[0] and BSEL[1], so no harm done, but this might be a bad sign of things to come.
Zuofu
Unfortunately, it seems that Intel implemented some new tricks in this series of CPUs. It detects the change, but drops my FSB down to 100Mhz. I'm guessing that the new chipsets also query the processor ID to determine the maximum operating frequency. I was able to restore my processor by tying together BSEL[0] and BSEL[1], so no harm done, but this might be a bad sign of things to come.
Zuofu