Pentium-M confusion.

I've been looking into the possibility of upgrading my laptop to a Pentium-M cpu, mainly for the speedstep feature and the battery savings that could give me. Looking on ebay I have found that there are a good few P-Ms for sale, a lot 400Mhz FSB and quite a few with 1Mb L2 cache, however when I look up the processor code (SL7FA or similar) on the intel website, most of them seem to say 'package type: 478 pin'.

Does that mean that these cpus are socket 478 or are they socket 479 but only use 478 pins or something? Are there socket 478 and socket 479 Pentium-Ms?

I am utterly confused.

 

People on eBay will sometimes get details wrong. The Pentium M and the Celeron you have, both use the same socket, which contains 479 Pins. I am not aware of any socket name, but people often call it socket 478, which isn't correct. Hope this helps.

 

well, not really. The info supplied on ebay is correct, as I can see the processor number on the cpu, but when i look up the codes on the Intel website, rthe Intel website says 'package type: 478 pin'

Assuming intel are not wrong, why does it say this? I think it could be something to do with only using 478 pins but having an extra one so it cant be plugged into a socket 478 motherboard, is that correct?

Can anyone shed light on this?

 

The 479-pin models actually have 478 pins, those P-M's (if they are Dothan-based) will worked perfectly. I also had a Celeron M and replaced it with a 533Mhz FSB Dothan-based Pentium M. I have the Radeon XPRESS 200M chipset.

You can find more information here: http://reviews.ebay.com/Intel-apos-...0000074521?ssPageName=BUYGD:CAT:-1:LISTINGS:3

 

Thankyou! That helps a lot. So you reckon a 533MHz P-M would be ok?

Having said that, most of the ones for sale are 400Mhz and nice and cheap to boot. Reckon my L100 would take a 2GHz Pentium-M? There's one for sale and it's tempting me...

 

Yes, however, even though my Toshiba runs at 533Mhz FSB, the memory runs at 400Mhz. With the Celeron M, FSB was 400Mhz and memory 533Mhz, so it's set to run FSB:Mem asynch (and there's no option in BIOS to change it), so if you don't mind running slower memory, go for it. For me the increased battery life and lower temps were worth it.

I would also recommend you to use NHC to undervolt that pentium M. Mine originally ran at 0.988V at lowest speed, and 1.356V at the highest speed. I undervolted it to 0.716V at lowest speed and 1.004V at the highest speeds, and adjusted the mid-steps accordingly. That way I gained almost 30 minutes battery life.

 

If it's that cheap, I would say go for it! If it's 400Mhz it has more chance of working. Keep in mind that opening your laptop will void your warranty.

 

Thanks! I'll try that.

Most likely i'll get a 1.5Ghz or 1.6GHz 400MHz FSB Pentium-M, then undervolt it, however, if I could get a faster chip I'd be interested. As I said above, i'm tempted by a 2GHz for sale.

 

Nice! Don't forget to apply some AS5.

 

That's a really nice undervolt, what Pentium M do you have? I have my PM 750 (1.86GHz/2MB/533MHz) undervolted to 1.1V/.780V.
ikovac, one of our 'hardware geek' ( ) posters, has an excellent article on undervolting the Pentium M:
http://www.thegamebooks.com/undervolting-intel-pentium-m---how-to-keep-your-gaming-cool-t78.html
The Pentium M 730 (1.6GHz) is a great value as far as I can see on eBay . . the prices may be different where you are though.

I am pretty sure that your notebook should be able to use 533MHz FSB Pentium Ms without problems. Jess, take a look at other configurations of the Toshiba you have and see what processors were offered.

 

Mine is a 730 (1.6Ghz) sSpec SL86G. I haven't tried 0.7 V yet, and perhaps I can go lower on the highest multiplier. Yours perhaps can't go lower on because of the high multiplier.

 

The 2GHz example will be expensive. There are lower speed cpus are more common and much cheaper.

A lot of the cpus for sale are the 130nm versions. Would that be detrimental in my quest for increased battery life?

This is the cpu I'm looking at. Isn't it a Banias core? Is that bad?

 

I would not go with a Banias (130nm). They require higher voltages and your motherboard may not be able to supply it.

 

ed22, you are running a Dothan Pentium-M? They are 1.34-1.4 volts whereas the Celeron-M you ran I presume was 1.26. The Banias are .09 something to 1.484. As I will be undervolting my Pentium-M anyway would it not be ok?

And did you find your Dothan ran ok at regular voltages?

 

Yes, mine is a Dothan 533Mhz FSB Pentium M. Original voltages are 0.988/1.356.
Remember that Banias, by being made on a 130nm process, will require more power, and perhaps you could not undervolt as much as in a Dothan-based Pentium M.

 

Cool, well I'd like a Dothan anyway. There's a nice looking P-M 715 on ebay that I hope to secure. That's 1.5Ghz, 400MHz FSB and 2Mb L2 cache. I figure I'll get similar performance from that to my current Celeron-M 380 and of course, speedstep and the ability to undervolt. That's a 1.34V so it should run ok before I undervolt it.

 

With that Pentium M, you can make the pin-mod to make it run at 533Mhz FSB, and that will get you a 2Ghz Pentium M.

 

Explain further?

 

Basically it's a mod where you connect two of the pin-sockets with a little wire, to make the motherboard "think" that it's running a 533Mhz FSB Pentium M (or Celeron M) and make it run at 533Mhz FSB, while the processor was originally set to run at 400Mhz FSB. There are step-by-step guides:

Here's a good guide: http://laptoplogic.com/resources/detail.php?id=35

Here's another one from NotebookReview: http://www.notebookreview.com/default.asp?newsID=3226&article=pin+mod

 

Would that not decrease my undervolting capabilities and hence eat my battery?

 

Well, yes, mostly at the higher multipliers.

 

I could, something to consider for the future, but for now I think the 1.5 with a nice undervolt should do well to increase my battery life. That's why I'm doing this in the first place!

 

Battery life will depend if you are running at the full 2Ghz, then certainly yes your battery life will dramatically decrease, however if you run in adaptive mode then there won't be that much of a difference.

 

So if speedstep is on, it won't make much difference?

For low battery running i'd use Toshiba Power Saver and limit the speed of the CPU. I believe it has 4 levels, 1-4, 1 being minimum (600MHz?) and 4 being maximum (being in this case 1.5GHz) so presuming a linear scale i'd limit it to probably 900MHz. Fortunately I just changed from a 933MHz PIII laptop and I know what can be done with 900MHz! a 900MHz P-M would kick a PIII anyway. If I changed it to 533MHz FSB I presume my minimum speed would go up as well to around 800MHz?

Pretty sure the L100 was available with Celeron-M, Core Solo and Core Duo. I don't think it was ever offered with a Pentium-M cpu.

 

I once tried Toshiba Power Saver, but it would not let me save my settings (don't know why), therefore i use NHC, which is what let me undervolt my Pentium M. And yes, the minimum clockspeed will be 800Mhz. The available multipliers will be 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 for a 2Ghz Pentium M. I even ran Windows Vista RC2 with Aero Glass on the 800Mhz setting! Decent performance. I would say that with adaptive, you get 95% of the battery life of running at a locked 800Mhz, while maintaining a fairly superior performance. Of course, if you load the processor heavily, it will drain the battery faster.

 

In NHC did you try setting your power settings to TPS? I like TPS as it's great for changing power settings to do with all aspects of the laptop that are variable, I hope to be able to use it in conjunction with NHC undervolts, although I may use NHC to regulate cpu speeds if possible.

I don't think I will do the pin mod as a pin mod + undervolting sounds like a bad plan, plus I don't need the performance, just the battery life.

 

You may try using both, but I'm not sure if TPS will override the undervolts.

 

I'll be annoyed if I can't as TPS regulates monitor settings much better than windows can as far as I can see.

 

A Banias Pentium M won't be compatible with your motherboard; it is a first-gen Pentium M and was used in the original Centrino platform which used different chipsets (Intel 855).

Hold up - I think you confused something. If your laptop can take a Celeron M 380 then it can take a Pentium M (your laptop takes Sonoma; Dothan Pentium Ms (7x5 sequence) used a different chipset). However, there is no way it can take a Core Solo/Duo unless Toshiba had a model of the L100 with a different motherboard.

 

Well that clears that up. Thanks Chaz.

Ok now you're confusing me. I presume Sonoma is the Centrino Platform on which the Dothan Pentium-M sits? Does my x200 chipset negate the presence of Sonoma in my laptop? I presume as my current cpu is a Celeron-M 380 (based on the Dothan Core 90nm architecture) then I am looking for a replacement Pentium-M with a Dothan Core, be it a 400MHz or 533MHz example. I would expect a 400MHz example to be more compatible as my current cpu also has 400MHz FSB.

They did. The Celeron-M range of Satellite Pro L100s have an x200 chipset and 256mb IGP. The Core based units have Core Solo and Duo cpus and an Intel 945 chipset with a 128mb IGP.

 

If your mobo takes a Dothan based processor, then it surely will take a Dothan based Pentium M, be it 400Mhz or 533Mhz. The only limitation will be the BIOS, that is, if it has support for 533Mhz parts.

 

Hence my thinking of getting a 400MHz FSB Dothan (7*5) Pentium-M, probably a 715, 725 or 735 depending on price and availability.

As I said, right now I'm liking the look of a 715 on ebay that'll finish on Friday morning.

 

Sonoma and Dothan Pentium M processors are not the same; the Sonoma has a few architectural tweaks, in addition to a faster 533MHz FSB.
I would suggest doing a little more research as to what your laptop can take; it should be able to take a Sonoma CPU but I am not certain.

 

Could you post a link where the differences between first generation (400Mhz) and second generation (533Mhz) Dothan's are shown? I'm just wondering what the differences are.

 

I think you've got yourself mixed up a bit here Chaz.

I thoroughly researched the whole subject last night to try to ascertain what cpus would be compatible with my machine.

Dothan is the name of the 90nm architecture of the 700 series Pentium-Ms, regardless of FSB.

Sonoma is the name of the updated Centrino platform designed to work with the newer Dothan Pentium-Ms.

 

Here's a link that can clear things up: http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2129

 

Dothan is the 90 nm processor, and sonoma the platform using the later adaptation of this processor (740, 750, 760 etc) with the 915 chipset and a 533 Mhz FSB. The platform using the 855 chipset and banias or early dothan processors (715, 725, 735 etc) at 400 Mhz FSB was known as carmel.

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

 

Yes, the core of the processors, not the platform. The Dothan Pentium Ms are different than the Sonoma-platform Pentium Ms as stated; they use different chipsets. I am almost positive yours takes the Dothan (Sonoma Platform) Pentium M CPUs:
-Pentium M 730
-Pentium M 740
-Pentium M 750
-Pentium M 760
-Pentium M 770
-Pentium M 780
I believe there are subtle changes in the architecture in the Sonoma CPUs vs. The Dothan as well.

 

The Radeon Xpress 200M will take both the 400Mhz FSB and 533Mhz Pentium M's.

 

As it's not an intel chipset I'd imagine that to be true, yes. I see no reason why 7*5 P-Ms wouldn't work on Sonoma, i think Sonoma is just capable of 533MHz fsb as well as 400.

 

As a matter of fact, the first user that I read that upgraded from a Celeron M on a XPRESS 200M did it to a 400Mhz Pentium M. You can read it here: http://www.hardforum.com/showthread.php?t=991427