No, I know what I'm talking about. But look here, on the Intel site. These are BOTH Pentium-M 750's, exactly the same specs, but the socket is different. what the heck?

750 S478

750 S479

And there's lots of these examples too, check the Intel Spec Finder

'Socket 479' is a bit of a misnomer as there are actually 478 pins. The pins are layed out differently to the 'normal' Socket 478 and are not compatible.

Yes. But as far as I know, there aren't any "normal" 478-pin'd Pentium-M's. The Pentium 4-M's are, but not the Pentium-M's. Is intel trying to say that the ones labeled with 478 is ACTUALLY the normal P4 478 layout?

It's always confused me too and I've done my research! One thing we can say for sure is that no matter if it has 478 or 479 pins it still won't work in a desktop unless it's one of those designed to handle Pentium M's.

Let me know if you come up with an answer.

Obviously we'd need special platforms, either the ASUS convertor or the dedicated motherboards. Here's the thing. We KNOW the 479's will work, but the ones labeled 478........ where are they used? I mean, if BOTH the 479 and 478 Pentium-M's are being offered in laptops, there must be no difference in socket design. I have only seen / heard of ONE single type of Pentium-M socket design.

As Quiet Riot mentioned, I think they both actually have 478 pins and yes there is only 1 pin layout for the Pentium M so either should work fine.

If you check Intels web site a little more closely -and specifically, This pdf document (section 4) you will see that the P-M is available with a 478-pin Micro-FCPGA packaging and a 479-ball Micro-FCBGA package. And later that pin B2 is depopulated on the FCPGA variant.

BGA (ball grid array) is useful when mounting components (permanently) directly onto a board, and in this case is for "thin and light" notebooks where you select the smallest packaging for everything to make it fit.

HTH

I see. which means the 479 BGA's are not in pin form, instead they are permanently attached to the board, meaning we won't find them for sale anywhere, even in 2nd hand right? So, the 479 BGA is an embedded chip?

Thanks |Romeo|, I always skip straight to the pin layout pages

That's right.

Obviously, nothing is ultimately unremoveable if you try hard enough; but to all intents and purposes.

well hahaha........... I mean, when we remove them there wont be any pins on the processor and may god pity the one who tries to solder 478 pins onto it!!

This sounds good, but I'm still encountering a wall with this whole 478/479 thing. For one, if a 479 chip is never to be found in the wild, why is there an adaptor made by ASUS that allows a 479 chip to be put in a 478 board? Clearly this means there are 479 PIN chips out there, and I have found sites that indicate they sell them, though they are rare.

My question is more exact. If you buy an AOpen cube barebones system that includes a MB that is socket 479 (pentium M), does a socket 478 pentium M chip work in it since that's pretty much the only thing you can buy at major sites like NewEgg? I see a lot of indication you can't, and none that you can, but why in the name of Bill Gates would you make a MB that is 479 if all the chips for sale are 478? Something isn't adding up here and I can't find any clearly stated answers from any of the companies involved.

All mobile Pentium M and Celeron M processors are by definition 479 pin processors.

Then why do resellers seem to all list them as 478 pin, as well as the specs on intel's site listing both 478 and 479 pin versions? Seems weakly defined to me.

it's just that the outside footprint looks like 479 pins. in fact the ACTUAL count is 478 pins.

Was about to start a new thread but found this one by searching so will append here.

I'm about to buy the AOpen i915GMm-HFS Socket 479 Intel 915G Micro ATX Intel Motherboard from NewEgg, so I decided to see if they also sold the CPU. Going over to their CPU page, I found (eg) Intel Pentium M 760 Dothan 533MHz FSB 2MB L2 Cache Socket 478 Processor but no Socket 479s. Since these are $300+, I wanted to be sure I was buying the right thing, so I contacted NewEgg; they told me to contact the equipment manufacturers as they could not say.

I looked on Intel's site, and got no good warm and fuzzy. I found this very interesting page, that seems to confirm there are two variants of just about every chip specification (scroll down to the Dothan section).

Since I'm transitioning from the 'interesting bit of research' phase, to the 'about to part with hard earned money' phase, is the general consensus out there that I plonk down my hard earned money on the "Intel Pentium M 760 Dothan 533MHz FSB 2MB L2 Cache Socket 478 Processor" and it will be the perfect partner for the motherboard in question? This does seem to be un-necessarily unclear!

Yes!

I don't think it is, you know; if you go the Pentium M spec page, it very clearly states that the P-M is made in 478 and 479 packages; you want a 479, because the AOpen M/B is socket 479. IIRC socket 479 CPU's are not electrically compatible with socket 478 and vice versa.

Don't know if it's too late now, but make sure you read the Turion article that was just posted. Seems that the AMD notebook chips are just as nice on the desktop as the Pentium M's ... and they're much cheaper.

Did some more Googling, came across this (buried in this rambling thread)
================
"P-M's come in two packages: a 478-pin flip-chip-pin-grid-array (FCPGA) that fits into a Socket-479 (somewhat counter-intuitively!), and a 479-ball BGA package for the ULV parts (soldered directly onto the mobo, no socket used).

I think that's where the confusion originated.
The 478-pin P-M is NOT pin-compatible with the socket 478 of Pentium 4's, and has one pin displaced to prevent improper insertion into the wrong socket. "
=================

and also (from here):
===================
However, it can all get a bit confusing as the processor socket on the AOpen board is known as Socket 479, but Pentium M is actually a Socket 478 chip. Although a Pentium M looks like a Socket 478 Pentium 4c without a headspreader, it's not pin-compatible with 865/875 motherboards. Socket 479 Pentium Ms do exist but they are pinless processors for the embedded market.
===================

I also note that the NewEgg page for the mobo in question shows 'Also Purchased' ... the socket 478 CPU.

So I guess the 478-pin guy is the one to get for the 'socket 479' motherboard .... but boy, what a confusing state of affairs!


I hate to switch gears this late in the game, but ... I honestly have no real pressing need for the system, so ... I guess I could take a look at the article! I thought Mobo availability was the problem - even fewer than for the Pentium M - but if that situation is chaging, then I'd be very interested!

It is not. As you have noted, Pentium M's cannot be inserted into a standard socket 478 motherboard. The Pentium M has 478 physical pins, but it is a socket 479 package. Yes, it is very confusing; perhaps this is a deliberate marketing strategy on Intel's part to keep the P-M concentrated in the laptop market; or perhaps they simply don't care that it's confusing.

I can imagine Intel not caring, but you'd thnk AOpen would somehow make a statement about 'what CPU to buy for our motherboard'. When you are shelling out $300 for a CPU, mail-order (i.e. difficult to return), you kinda need to know you are getting the right thing.

In this case, it would appear the motherboard socket is referred to as "Socket 479" while the corresponding CPUs are labeled '478-pin'; presumaby to differentiate them from the ball grid array versions, which are '479-pin' - and which, presumably and ironically, won't fit into the 'socket 479' because they are designed to be surface-mounted in low profile systems! I guess the good news is, you can't actually buy a 479-pin, ball grid array version in retail channels, so you eventually come around to realizing you need the 478-pin!

Commell's website (another maker of Pentium M boards) does say this, for the CPU: "Micro-FCPGA 478 Mobile Intel Pentium M / Celeron M CPU
up to 2.26 GHz @ 400/533 MHz FSB"; interestingly, they don't make mention of the socket type at all.

Aopen's website simply says "Intel Pentium M CPU (Dothan / Banias)
Socket 479" and does not address 'how the CPU is referenced'. I did a site-wide google on AOpen's website, and could not find one reference to the need for a '478-pin' CPU.

Regarding MikeC's reassuring statement that "All mobile Pentium M and Celeron M processors are by definition 479 pin processors",
I believe it may be more accurate to say, '...are by definition socket 479 processors' - since Intel themselves clearly label their Pentium M's as being 478-pin and 479-pin in their own literature.

Anyway - I'm convinced that the 478-pin Pentium M is what I need for the AOpen board ... but this is a good example of poor labeling if ever there was one! This thread is the best reference I could find on the web that deals with this issue! I would recommend a post-script to the AOpen motherboard review on the site, to short-circuit this obvious line of confustion for others embarking down the Pentium M path! You guys obviously used a Pentium M CPU, and it had an sSpec number; that sSpec number should translate to an Intel speclist, which - presumably - would say, 478-pin. That would be the most reassuring thing of all!

Thanks for everyone's time!

Slightly different variation of the same question. I have a spare Celeron M CPU as I recently upgraded my laptop to a Pentium M (Much better). I thought the Celeron M might make a good HTPC. The cheapest motherboard I could find is this one:

MSI 915GM Speedster-FA4R Socket 478 Intel 915GM Micro ATX Intel Motherboard

Sounds good. Except there's this note:

On Intel Pentium-M/Celeron-M Dothan CPU, with a choice of 478pins and 479pins P-M CPU socket, MSI designed 478pins P-M CPU socket on this board.

Reading what was stated earlier in the thread, it would seem it would work as the Celeron really has 478 pins. But if all Pentium/Celeron M CPUs are 478 "pins", then why is this statement even mentioned? Is it to clear up the socket 479 having 478 pins?

My head a-splode!

Psssst... Hey everyone.

If your Pentium/Celeron M motherboard comes in a retail box and your Pentium/Celeron M CPU comes in a retail box - they are going to work together. You can safely ignore all the pin-socket distinctions and confusion.