how to determine pll on T41 motherboard ...

[T400plus]

where can i find the details to feed into clockgen?.

[Binh]

where can i find the details to feed into clockgen?.

The PLL is located under touchpad, or more exactly, in the upper right corner (edited: left side, not right side).
AFAIK, the are only two types of PLL in T4x: unoverclockable ICS 950810 and overclockable CY28346. However, both can be overclocked by pin-mod.
If you have CY28346, you can overclock to 110FSB by using SetFSB software (X31 version). Higher FSB frequency may cause LAN card and Sound to stop working.
ClockGen can not overclock any of the two above PLL.

[T400plus]

thank you very much.
On one of my T41 (the fried one )it is 950810PG .
I will open up my other T41 later to see what it is. I presume it will be same.so no setfsb for me ...
It is on the left of the big black chip (below the touch pad).

[Binh]

It is on the left of the big black chip (below the touch pad).

Yes, I am wrong. The PLL is on the upper left side under touchpad.