Thinkpads Forum

This is going to throw a serious spanner into the work of everyone trying to figure out what 600x can speedstep and run the 850 cpu at top speed.

Recently I got my hands on the rare MMC-2 850 cpu and quickly whipped open my 600x and popped out the 500 cpu and and put in the 850 - I knew this wouldn't run at top speed but even 150 less would be good I thought.

Sure enough I checked the speed with cpuinfo 1.3a and it said the speed to be around 700. Great I thought. However I then started working on just battery and checked cpuinfo 1.3a again and this time it came back at running at around 850!!! I then re-plugged it in and sure enough I'm still running at 850? I checked again with a different freeware speed checker and it came back the same. How can this be? Has anyone else experienced this? Shall I test the cpu speed with a different program - any suggestions for which program I should use?

Does this change current thinking on the speedstep models etc?

Sorry just wanted to add that I did a BIOS update yesterday to the latest one - could this be it? When I was checking the speed and it was at 700 this was prior to the BIOS update then after the BIOS update is when I noticed the higher speed.

That's GREAT News! Congrats!!

Mannersxxx wrote:How can this be? Has anyone else experienced this? [...] Does this change current thinking on the speedstep models etc?

I think that the current belief is that if you are using Windows 2000, it may be possible to achieve the maximum CPU speed with an upgraded SpeedStep CPU on certain non-SpeedStep 600 series machines.

The theory behind this as I understand it is that the Windows 2000 processor drivers and/or power management software must include some kind of built-in CPU throttling. In some cases, this can appear as though the CPU is employing SpeedStep hardware instructions, when in fact it is actually employing a software-dependent Windows 2000 CPU speed throttling.

There is also a theory that certain 600X machines that shipped with non-SpeedStep CPUs may contain motherboards that support SpeedStep, but no one has been able to create a definitive list of such machines.

And I also have a theory that there are minor differences between the PIII 750, 800, and 850 MMC-2 boards that cause these different CPUs to react slightly differently in different contexts, making testing across different systems very difficult.

I don't recall seeing anyone before this describing reaching the max CPU speed in a non-SpeedStep 600X, but a couple have reported doing so with non-SpeedStep 600E machines. I personally tested my 770Z with a PIII 800 and a fresh install of Windows 2000 SP4, but I was unable to reach the 800MHz max speed in that config. But someone else claims to have reached the max speed with an upgraded CPU in a 770Z.

Thanks for reporting to the forum on this and giving details of your setup and experience. I would be VERY interested in knowing if you were able to achieve the same effect under Windows 98SE or Windows XP.

For additional information, consult the following threads:
SpeedStep and Windows 2000 on a ThinkPad 600E
and
600x (non-SpeedStep) with 850mmc-2

Phil.

Ok great that's extremely helpful. Still peculiar that the cpu speed changed when the BIOS was updated though - suggesting a change in the hardware?......

Also despite my surprise and happiness at this CPU speed I'm concerned its going to eat through my battery life when not on AC. Should I download this:

http://www-307.ibm.com/pc/support/site. ... IGR-4HLVUP

or is there some other way - perhaps some freeware which means I can shift the speed of the cpu when on battery.

OH NO!

Did a restart and now running back at 700mhz.

Whats going on?

I'd suggest you try to run DeepSleep. Maybe, just maybe, your board/CPU/Combination of the two will react to it even without the hardware mod.