PAE Processor Choices for T41, etc ?

[coors]

Like many others before me I found out that when installing Linux the Intel CPU in my T41 is non-PAE, physical address extension, and that forcing PAE is required for these opensource operating systems to function. After a lot of reading I discovered that some of the late T4x series came with PAE CPUs. I also noted when I updated the BIOS to 3.23 that the upgraded BIOS supports certain AMD processors. Is there a list, somewhere, that shows all of the compatible CPU choices for my machine, and other T4x machines, and whether these CPUs are PAE or not?

[dr_st]

The 533MHz Dothans, which came with the T43, support PAE.

I think it should be possible to put one in a T41, but it will run at a lower speed (because of 533-->400MHz bus reduction). I don't recall if other tweaks are needed to get it to work or not.

[Cigarguy]

AFAIK, there never ever was a machine who had a motherboard that will take an Intel CPU or AMD CPU. It is one or the other not both. Your problem of PAE/non-PAE cannot be resolve with a BIOS update.

You choice is to find and probably overpay for one of the few PAE CPUs for the T43 and try to make that work (some googling is required by you) or look for a non-PAE Linux distro. There's a few pretty good non-PAE specific Linux distro if you look. I myself have recently install Crunchbag and like it. The other option is Win 7.

[ajkula66]

The 533MHz Dothans, which came with the T43, support PAE.

I think it should be possible to put one in a T41, but it will run at a lower speed (because of 533-->400MHz bus reduction).

Correct. These are quite inexpensive nowadays, apart from the PM 780 which is the fastest one.

I don't recall if other tweaks are needed to get it to work or not.

There is a pinmod which enables these CPUs to run at full speeds, although I've never performed it myself.

[coors]

Thank you for your replies!

@dr_st Yes, thats the one I've been looking at, Pentium M 780 2.26 GHz. Ok, so 400/533 = .75 x 2.26 = 1.695GHz w/2MB cache. Besides giving me PAE, I wonder how this will perform compared to the 2.0GHz w/1MB cache.

@cigarguy I stand corrected then as the 2x Linux OSs that I loaded to SATA drives, via Ultrabay Slim Adapter, both required forcing PAE. I'm not comfortable doing that as I don't know how it might be overtaxing the CPU or other components. As for the AMD and Intel CPU in same machine, you're absolutely correct. To quote, the readme file for this BIOS update says:
"3.23 (1RETDRWW)>
Note:
This BIOS version will only work with Embedded Controller Program
Version 3.04 (or higher).

- (Fix) ThinkPad will not resume after undock from a docking station
while a system is in hibernation mode.
- (New) USB storage drive letter handling modified.
- (New) Support for a new video memory for certain AMD video chips."
Somehow I misread and believed that it was reffering to AMD CPUs.

I believe that there may even be a higher yet specification CPU, that I read about someone using, but I have not found that information again, as of yet.

[coors]

@ajkula66 Do you have a link to this pinmod. That is very interesting information, indeed!

[ajkula66]

Thank you for your replies!

@dr_st Yes, thats the one I've been looking at, Pentium M 780 2.26 GHz. Ok, so 400/533 = .75 x 2.26 = 1.695GHz w/2MB cache. Besides giving me PAE, I wonder how this will perform compared to the 2.0GHz w/1MB cache.

There is no PM 2.0 CPU with 1MB cache. Those already had 2MB L2 cache.

I believe that there may even be a higher yet specification CPU, that I read about someone using, but I have not found that information again, as of yet.

No there isn't. PM 780 is as good as it gets. Period.

Unfortunately, I don't have a link to the pinmod...never bookmarked the thread since I had no interest in trying it out.

[dr_st]

AFAIK, there never ever was a machine who had a motherboard that will take an Intel CPU or AMD CPU.

Back in the day (Pentium 1 era) there actually were such machines. It's almost impossible to believe. Socket 7 boards took certain Intel, AMD and even Cyrix CPUs.

http://en.wikipedia.org/wiki/Socket_7

[Cigarguy]

Back in the day (Pentium 1 era) there actually were such machines. It's almost impossible to believe. Socket 7 boards took certain Intel, AMD and even Cyrix CPUs.

http://en.wikipedia.org/wiki/Socket_7

Hot dang, wouldn't that be nice had that became a trend then standard. Thanks for the info.

[axur-delmeria]

Back in the day (Pentium 1 era) there actually were such machines. It's almost impossible to believe. Socket 7 boards took certain Intel, AMD and even Cyrix CPUs.

VIA Cyrix III and early versions of the C3 processors were compatible with Socket 370, used by Intel's Pentium 3 processsor. :O

Performance was subpar, but power consumption was low.

[RealBlackStuff]

The problem for OP is still unsolved:
he has a T41 motherboard and wants to put in a T43 CPU.
Doesn't work that way, you'll also need a T43/R52 motherboard (with different DDR2 RAM).

[Neil]

or look for a non-PAE Linux distro.

This is the way to solve the problem. Modding a T41 for PAE support costs money and a lot of time, while installing a distro with a i486 kernel that will work with the T41 as-is, is quick, easy and free.

[coors]

I had an image in this post that a moderator didn't like the size of. It was then showing some personal info that I didn't want seen, so I quickly erased my post. Now that I have the time to edit this post, I have no idea what this post originally contained. Sorry for the inconvenience.

[ajkula66]

I found a page on Thinkpad CPU pin-modification and it dealt with modifying M-755, M-765 and other 400MHz CPUs to run overclocked in a 533MHz socket. That page mentioned that the pin-mod was not possible for the M-780 processor.

It's a different mod. You're not looking to overclock the CPU, but to fool the board into "seeing" the CPU as the 400MHz one, while maintaining the instructions set from the 533MHz setup.

[coors]

@ ajkula66 Thanks! I'll keep looking for that one then. It would be much more than just great if I could get that CPU to work at full specification in the T41.

[ajkula66]

FWIW...Fedora 20 runs great on my sickly T42p, and CentOS on the A31p.

There are many distros that maintain support for non-PAE CPUs and - as previously mentioned - present a faster and easier course of action than pinmodding a 533MHz Dothan.

Good luck.

[irus]

you can get windows xp updates till april 2019 with a simple registry hack.

[coors]

Alright, I've decided to just leave the T41 as is and use Win-XP as my OS for this machine. The modifying CPU, changing MB or finding a non-PAE Linux OS is more than I'm willing for, at this juncture. I really do appreciate all of the information that you took the time to share with me, as it helped make my final descision possible.

@irus Thanks for the suggestion!

[coors]

Revisiting this thread with new info. I found this quote, by FrankL: "actually, the 400 Mhz Dothan CPUs do support PAE/NX, but lack the CPU feature flag(s) for it. Since not too long ago, the Ubuntu 12.04 PAE kernel boots happily off these old CPUs by ignoring the lack of advertised features"

Originally, after installing Xubuntu and doing all of the updates, I noticed that the T41 was running hotter and louder, with Xubuntu, than with XP. Therefore I believed that the "non-PAE" 2GHz Dothan cpu was not a good idea to use with Xubuntu. However, I decided a few days ago to see what would happen if I continuously used Xubuntu with this processor. After a day or so it wanted to do more updates, kernel firmware, etc. and after it rebooted it has actually been running quieter and cooler than XP. That coupled with FrankL's quote, above, leads me to believe that it is probably perfectly safe for me to run Xubuntu with the Dothan processor.