Overclocking a T42?

[NotANitWit]

Is it possible to overclock a Thinkpad? The T2X series was, which gave my brother endless bragging rights since at the time (circa 2000) the mobile P-III would clock higher than the desktop version, so it was the faster than the best desktop machines! I'm curious what the headroom is on the new Dothan Pentium-M chips.

Even if overclocking is possible, I wouldn't recommend it very much, but I'm very curious and kind of eager just to try.

One possible method would be with software like SoftFSB.
http://www.geocities.com/enigmadeadsouls/softfsb.html

The problem is that you need to know the specifics of the clock generator on the T42's motherboard, which I can't figure out.

Thanks for any ideas or help!

[NotANitWit]

Followup to my previous post.

It turns out that the 2.0GHz T42 is indeed overclockable with SoftFSB,
though pretty much as a party-trick since the speed boost will go away as soon as you reboot. Finding the limits is also frustrating because of the many reboots when the laptop crashes/freezes.

My T42 has a 755 Dothan in it, so it's already top-end 2.0Ghz, but it turns out there's a lot of headroom in there! I had no problem reaching 2.3 Ghz!

However the speed seems very heat limited. As evidence, if I start the laptop after a long cooldown (turned off for 1 hour), I can run at 2.5 Ghz for about 5 minutes while running Prime95 (a CPU stress tool) before errors appear. 2.3 Ghz seems fine forever.

Kudos to IBM (and Intel) for making sure the 755 T42 can handle the full 2.0 Ghz with so much safety margin. This implies that you could even let your machine cook in sunlight on a hot day and it's not going to be unreliable since it's at least 15% below its real top speed.

[plucky duck]

So you're saying that you've found the proper clock generator and overclocked the T42? What fsb/multiplier/voltage settings did you use?

Wonder if it's the same for the X31 and whether it's possible to overclock the P-M 1.6Ghz proc.

Seems very dangerous to do in a laptop enclosed environment. Not to mention voiding warranty as well.

[NotANitWit]

You can't change the multiplier or the voltage AFAIK... though I wonder about that since doesn't Speedstep manipulate both?

I just increased FSB from 200 to 228. That seemed to be the stable limit.

I didn't try all the peripherals though, I wouldn't be surprised if something like the modem port or IR or whatever got annoyed at being run faster than it was used to.

I had to force full speed CPU mode, Adaptive mode caused strange things to happen (read, crashes). Also, a lot of repeated changes with the FSB was bad, it was always best to reboot, then change FSB once.

Yes, the closed laptop was definately a limit, imagine what a P-M would do with one of those 1-kg heatsinks on it, or watercooling!

I doubt I voided the warranty, I never opened the case, I only ran software.


But this isn't BIOS based overclocking so it's not really great, more of fun to experiment with as opposed to a perminent way to get a speed boost. Too bad!

[plucky duck]

In that case....

You don't happen to know what clock generator is for the X31 eh?

[edelrc]

NotANitWit, I am with you.
Now we do not only know the capacities of our notebooks, but also we learn a deal also on how they design it in first place.
By testing the limits of what surrounds us it is the way our the society progress. Terrific job done with that processor!
Thanks in name of the fascinated out there, (or that those that are afraid to tests the limits of their loved ThinkPads…)

[mtbiac]

is it possible to overclock the 9600 64mb on the T42?? if so, how? is it permanent or do you have to change it every time you reboot?

thanks

[Conmee]

You can use RadLinker or RadClocker to OC the video (both Radeon and FireGL) and set it on a permanent basis or on a per-game/per-app basis. From a battery life and system life standpoint, better to just OC when you're playing a game or need/want the extra horsepower. I believe RadLinker also comes with the Omega driver distribution too.

Daniel