Intel Pentium Duo overclock

[CommandoCATS]

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

 

[stevty2889]

err, doesn't the core duo run at 166mhz FSB at stock speeds?

EDIT: yep, verified it, core duo runs at 667mhz FSB(166mhz) at stock speeds..so doing the BSEL mod to make it run at it's default speed isn't gonna really do anything..

 

[CommandoCATS]

I think only the higher ones (2.0 and 2.13) do. I could be wrong though, and that might explain everything.

 

[stevty2889]

There are only 3 models right now, 1.66, 1.83, and 2.16ghz. They all run at 667mhz FSB.

EDIT: on a side note, I tried doing a BSEL mod on my presler, and it didn't work(although it was a little tricker, since there are no pins on the CPU. Should have tried conductive silver paint instead of a soldering iron though.

 

[RichUK]

I have the Dell 9400 with a 1.83Ghz Yonah Core Duo, and the BUS already runs at 166Mhz 😕