Intel Mobile line

I'm a bit rusty in my Intel knowledge and even more so with Intel mobile's.

As far as performance is concerned, which mobile CPU would be at the top?

As far as power consumption is concerned, which CPU would give the best battery life?

As far as price is concerned, which, in your opinion, would be the best CPU?

And is all this about Celeron-M's being completely different from the old Celeron line true? How do they fare against the Pentium-M's?

The best mobile chip from intel is the 780. It runs at 2.26GHz and has a 4x133MHz FSB.


The best for power consumption would be any of the ULV Pentium M's. I think they range from 1ghz to 1.2ghz or so.

The best price/performance is the 740. It's 1.73GHz and costs usually about $250 for the chip itself.

The Celeron M is the first Celeron in a long time that didnt suck! It has a 1MB cache, and performs very similarly to the Pentum M. It just has less power saving features and is as of this post limited to a 4x100MHz FSB.

I've noticed that laptops with the Celeron M's are significantly cheaper than the Pentium M's. Would their price/performance ratio be more worthwhile than a Pentium M?

How do the Celeron-M's and Pentium-M's compare with the P4's in performance?

It also depends on how you define 'mobile'. Several makers produce laptops using desktop P4s, so you could get a laptop with a P4 670EE running at 3.8Ghz, which would destroy the 2.26 P-M. Then again the P-M would absolutely destroy the P4 in battry life, so it depends where your priorities lie.

get a 1.6 400 bus pentium m and nail polish the pin for 533 mhz goodness, my next setups going to be dothan based, gonna get ~3 ghz and 275~300 fsb, considering dothan at 2.6 ghz and 160 fsb beats a fx-55, its sure going to perform dothans are cheap compared to the competition performance wise after ocing, almost every 533 fsb dothan will see 2.8 ghz and many see 3+ ghz and it does it all on a dinky heat sink

Originally Posted by ryuji

get a 1.6 400 bus pentium m and nail polish the pin for 533 mhz goodness,

You actually have to short BSEL0 to ground (= low), not isolate it (= high), to mod it to 533MHz.

Short these 2 pins: http://img195.echo.cx/img195/6821/step12uv.jpg like this: http://img195.echo.cx/img195/1852/step1z0ah.jpg , or (shudder) drop a U shaped wire into the socket.

Originally Posted by pxc

You actually have to short BSEL0 to ground (= low), not isolate it (= high), to mod it to 533MHz.

Short these 2 pins: http://img195.echo.cx/img195/6821/step12uv.jpg like this: http://img195.echo.cx/img195/1852/step1z0ah.jpg , or (shudder) drop a U shaped wire into the socket.

my bad either way no use in buying a high end dothan when you can just do that to a low end one and save a ton of money, at least for laptops, for overclocking on desktops, thats another story

Any explanation as to why shorting 2 pins on a CPU works? Seems a bit scary, especially when I don't know why this is possible.

What is exactly happening when you short the two pins?

you're pulling the FSB signal select low. this forces it to a certain FSB.
its like the old motherboards where you actually use jumpers.

Originally Posted by CoW]8(0)

Any explanation as to why shorting 2 pins on a CPU works? Seems a bit scary, especially when I don't know why this is possible.

What is exactly happening when you short the two pins?

There are 2 pins on the CPU called BSEL0 and BSEL1 (aka BSEL[0:1]) that control detection of the bus speed. A motherboard has circuitry to read those signals. Due to the pull up resistors in that circuitry, a pin with no connection is read as a high (1 or H) and a pin that is connected to ground is read as a low (0 or L).

Intel ships the CPUs with different combinations of BSEL pins disconnected and connected to ground, depending if the processor is shipped at 400MHz or 533MHz FSB. The encodings for Dothan are:

BSEL[1] BSEL[0] BCLK Frequency
  L       H       100 MHz
  L       L       133 MHz
  H       L       RESERVED
  H       H       RESERVED

The BCLK frequency is QDR, so 100MHz QDR = 400MHz effective FSB and 133MHz QDR = 533MHz effective FSB.

A more concrete example: notice above that a 400MHz FSB Dothan ships with BSEL0 High (disconnected) and BSEL1 Low (shorted to ground). Shorting that disconnected pin to ground makes the processor the same as the 533MHz FSB version since BSEL0 and BSEL1 are now both shorted to ground.

The same concept also applies to desktop processors and FSB speeds can be varied between 400/533/800/1066MHz using similar methods of isolating and shorting pins to ground.

Why aren't these jumpers found on the motherboard? Has Intel been selling these Pentium M's in different categories? Same exact chip with different jumpre settings?

Originally Posted by ryuji

get a 1.6 400 bus pentium m and nail polish the pin for 533 mhz goodness

one friend of mine just did it (i persuaded him to do so ) and now he is in trouble.
has acer laptop with ddr2-533 sodimms inside.
bad thing is that no matter if 400fsb chip is @ 100fsb or modded to 133 - it boots up with 400 strap and 3-3-3 timings and 1:2 ratio.
unfortunately those rams won't do 533mhz with those timings and acer laptop is too smart, reads spd values using cpuid not bootup value
any ram recommendations?

Originally Posted by markku

one friend of mine just did it (i persuaded him to do so ) and now he is in trouble.

Isolating BSEL0 on a 400MHz FSB P-M does absolutely nothing. It's already not connected from the factory. Read the posts above for the correct mod technique.

So presently the highest fsb a Celeron M has is 400mhz? But it's performance is still very comparable to a Pentium M with same clock/fsb?


And according to this. The Celeron M's lack speedstep. Does it have any power saving abilities?

Originally Posted by ryuji

get a 1.6 400 bus pentium m and nail polish the pin for 533 mhz goodness, my next setups going to be dothan based, gonna get ~3 ghz and 275~300 fsb, considering dothan at 2.6 ghz and 160 fsb beats a fx-55, its sure going to perform dothans are cheap compared to the competition performance wise after ocing, almost every 533 fsb dothan will see 2.8 ghz and many see 3+ ghz and it does it all on a dinky heat sink

?! A Pentium M can clock from 1.6ghz to ~3ghz on stock laptop cooling ?!

Originally Posted by CoW]8(0)

?! A Pentium M can clock from 1.6ghz to ~3ghz on stock laptop cooling ?!

no with high end air cooling, 2.8 max with the ct-479 heat sink

Originally Posted by CoW]8(0)

So presently the highest fsb a Celeron M has is 400mhz? But it's performance is still very comparable to a Pentium M with same clock/fsb?


And according to this. The Celeron M's lack speedstep. Does it have any power saving abilities?

It's got the same good idle power characteristics and slightly lower voltage than regular P-Ms. At idle, it uses only at most a couple of watts more than a fully stepped down P-M.

How do Celeron M's overclock under stock conditions (laptop)?

The overclocking which ryuji spoke of was on a desktop with a CT-479 adapter? The CT-479
heatsink looks very small and not very high end...

Originally Posted by CoW]8(0)

How do Celeron M's overclock under stock conditions (laptop)?

The overclocking which ryuji spoke of was on a desktop with a CT-479 adapter? The CT-479
heatsink looks very small and not very high end...

doesnt need to be high end, dothans make so little heat that water cooling is absolutly worthless, cant say that about any other cpu can you?(were talking about 32-40 watts of heat stock) thats damn close to the ammount of heat a typical chipset puts off to put it in comparison

i wasnt specific enough, the ct-479 sink is good for up to 2.8 ghz, you would need say a xp-120 to do 3-3.2 ghz(highest i have ever seen it, not too many ppl can get em past 3 ghz)

Had a bunch of Celeron M 350Js not too long ago. Those are 1.3Ghz chips, 1MB cache based on the Dothan core. All were able to get at least a 60% overclock with default voltage on desktop boards with no real overclocking ability and stock heatsinks. That's only around 2GHz, but in my opinion they'll go a lot higher with the right board and cooling.

Laptop overclocking is a different beast, but I'd imagine pretty much any Celeron M should be able to be bumped up to a 133MHz bus.