Can a P4-M be used in place of a Mobile P4 in a laptop?

[Creig]

I am considering upgrading the processor on my Compaq Presario 2500. Right now it has a 2.0Ghz desktop Celeron in it (TDP 52.8 watts). This laptop could come from the factory with either a 2.0-2.2 Celeron on a 100 MHz FSB or a Mobile P4 2.0-3.06 running 400/533 MHz.

Compaq Presario 2500 datasheet

However, I would rather go with a P4-M than a Mobile P4 for power consumption reasons.

Now here's the question. Will a P4-M work properly in a laptop designed for a Mobile P4? I know a P4-M will default to 12x in a desktop motherboard. I am assuming this is because the desktop motherboard is missing Speedstep circuitry. But would I still have access to the full/battery speeds of the P4-M processor if I used it in my Presario 2500? Does anybody have a link showing somebody who has attempted this previously? I can't seem to find anything and I KNOW this has already been tried.

 

[Creig]

Nobody has ever done this? I find that hard to believe.

 

[Ayah]

You might have to try it out and tell us what happens.

 

[LouPoir]

I thought the MobileP4 was S478. I am sure the PentiumM is S479.

Check over at notebookforums

 

[piasabird]

You void the warranty if you open the case.

 

[Brainonska511]

Originally posted by: LouPoir
I thought the MobileP4 was S478. I am sure the PentiumM is S479.

Check over at notebookforums

I think he's referring to Replacing a Mobile Pentium 4 with a Pentium 4M, 2 different types of processors.

 

[Creig]

Originally posted by: Brainonska511

Originally posted by: LouPoir
I thought the MobileP4 was S478. I am sure the PentiumM is S479.

Check over at notebookforums

I think he's referring to Replacing a Mobile Pentium 4 with a Pentium 4M, 2 different types of processors.

Exactly. The P4-M has a TDP roughly 1/2 that of the Mobile P4.

http://en.wikipedia.org/wiki/List_of_Intel_Pentium_4_microprocessors

Since I couldn't seem to find any definitive answer to my question, I said the heck with it and ordered a 2.4GHz P4-M. I'll give it a shot next week and see what happens.

 

[Megatomic]

Neat idea Creig. I have an old Gateway 400SD4 with a Pentium 4A chip and the Intel 845MZ chipset. I'd love to add a faster CPU to this thing.

I wonder how much I can beef us this lappie? :light:

 

[Creig]

Well, so far results aren't looking good. The P4-M boots just fine, but I'm stuck at the same 12x multiplier that the desktop motherboards do when running these chips. I've played around with the power settings to try and get the CPU to come out of its power saving mode and enable 24x, but no dice.

This is odd since this Presario 2500 could come with a Mobile P4 which is also a Northwood core SpeedStep processor. I'm guessing it might have to do with the BIOS not recognizing the chip since it originally never came with a P4-M, thus not enabling SpeedStep.

Any thoughts? I know I can install a Mobile P4, but they consume twice as much power as the P4-M processors do.

 

[Creig]

Just a thought... I know Windows XP SP2 has the SpeedStep driver built in, but is it installed even if a non-SpeedStep processor is detected in the initial installation? Is it possible that I would either need to manually install a driver or even have to do a fresh XP install in order to get SpeedStep working properly?

 

[Brainonska511]

Originally posted by: Creig
Just a thought... I know Windows XP SP2 has the SpeedStep driver built in, but is it installed even if a non-SpeedStep processor is detected in the initial installation? Is it possible that I would either need to manually install a driver or even have to do a fresh XP install in order to get SpeedStep working properly?

It can't hurt to try a reinstall of XP in this case. If it doesn't work, you'll know that the BIOS does not recognize the chip properly and locks it at the lowest multiplier.

 

[DaveVandorAmon]

I would try flashing the BIOS with the latest revision (if not already applied) and also try manually updating the "processor" driver for the newly installed processor. Also, there is an application I use on my P-M notebook and an older T30 that didn't seem to be using speedstep properly, that you can use to toggle the SpeedStep called SpeedSwitch XP. Hopefully that will work for you. Good Luck.

 

[Creig]

As far as I can tell, I already have the latest BIOS for my laptop. It has the PhoenixBios version 4.0 release 6.0 and, naturally, has very little in the way of user-adjustable settings. I did manage to take a digital photo of the POST info that flashes briefly on the screen every time you exit the BIOS and it correctly showed the P4-M 2.40 GHz information. So it appears the BIOS can at least correctly identify the processor.

I already tried using SpeedSwitch and Notebook Hardware Control and neither one was able to change the processor speed state to full speed (24x).

I also already tried updating the CPU using the Add New Hardware wizard, but the only Intel drivers shown were generic and there were three different drivers with a generic "Intel" lablel. I was also unable to locate an installable "Intel P4-M" processor driver online.

I suppose I could wipe out XP and reinstall, but I REALLY don't want to do that again. I just did that about a month ago.

Does anybody know of any SpeedStep experts I could contact about this? If I can solve this problem, it should open up new upgrade possibilities for people with older laptops like me.

 

[DaveVandorAmon]

AFAIK or can remember there were speedstep issues with XP SP1, and on some Dell laptops using P-Ms, they issued a fix for the issue preventing the processor from running full speed when plugged in, but I still saw problems with SP2 machines like the Precision M90 laptops running P-M 1.4s, they'd just stay at 800mhz. Although the T30 I was using that had a P-4M 1.8 also had the same problem. I'd check with this first, unless you have already Intel Processor Frequency Finder and make sure it recognizes the processor as a speedstep capable processor. Then check the device manager and make sure the driver it is using, I believe the
"intelppm.sys" driver for the processor, and not the older "gv3.sys" driver. Lastly, make sure that the CMOS is configured for Enhanced SpeedStep enable. As a last resort, you could perform an "in-place" installation of windows xp instead of a full installation and you would not lose your apps and data (although I'd back that up prior to doing so anyway.) to see if that fixes the issue. Also, you can try turning the setting in XP to Always On in the power options (but SpeedSwitch basically does that for you...so if that didn't work, this might not either.).

That's pretty much all I got except contacting HP/Compaq and seeing if there is a version of the BIOS for a different model type that is compatible with your board revision that will "support" the new processor correctly. Good Luck.