A20m with P3 850

[Izzm]

i read some guys are using a p3 850 mhz cpu in their old A20(m?).

ive got a A20m with a celeron 550 mhz cpu and upgraded it to p3 850, but it runs only with 700 mhz.
if my board wont use speedstep, the cpu would run with only 550 mhz, am i wrong?

so my question is: did you change anything else? like a jumper setting for a different voltage?
as i could read the 850 mhz cpu needs 1.6 V, maybe it gets in my board only 1.35 V (p3 700).

thanks and best regards, Izzm

[Phazer]

Maybe a BIOS upgrade is needed? I had the same situation on a T20 board that I put into a T22, it wouldn't run at full speed until I updated the BIOS. Just a thought.

[ajkula66]

Welcome to the forum!

Not every A2x board will run with higher-speed CPUs. I believe that there's a very informative post by sjthinkpader about that, you may want to use the "search" function to locate it...

[spuddog]

I made the same upgrade. I'm pretty sure that on a non-speedstep board the max is 700.

Scott

[sjthinkpader]

Here is a handy summary:

http://www.thinkwiki.org/wiki/Intel_Mobile_Pentium_III

All the dual core voltage CPUs can support SpeedStep. Single core voltage CPUs cannot support SpeedStep including all Celerons from those years.

http://www.thinkwiki.org/wiki/Intel_Mob ... on_%282%29

Support of the various CPU frequency is governed by a clock multiplier in the chipset. You can find the MB FRU number that will support 850Mhz CPUs in the Lenovo system parts lists. I have never attempted to flash the BIOS on these boards but instead looked for those boards that will support 1.70/1.35V core voltages for 1Ghz/900Mhz CPUs. If you do upgrade to these CPUs, you will also need the fan/heatsink assembly since they have some of the highest TDP at over 30W. Neverheless these are some of the most robust CPUs even at that kind of thermal power.

Problem with upgrading these machines today is that 100Mhz single data rate SDRAM will be too small and too expensive.