Need help from some knowledgeable Intel fans

[Creig]

Okay, here's the deal. I picked my wife up a new Sony Vaio so I inherited her old Compaq Presario 2500. It's not a bad laptop, but it does have an annoying quirk in that the CPU fan never shuts off while it's running. It has a 2.0GHz Socket 478 Celeron. Now if I recall, some companies used desktop processors in their laptops in order to save a few dollars. These processors run hotter and don't have the CPU throttling and other features that the mobile chips do.

The 2.0GHz Celeron in this laptop was the slowest CPU available for this model. But they went all the way up to a 3.06 GHz/533 Pentium 4.

http://www.hp.com/hpinfo/newsroom/press_kits/2003/pcs/2500datasheet.pdf

According to CPU-Z and WCPUID, my processor is a 0.13 Northwood running on a 100 MHz FSB. Family 15 (F), Model 2, Stepping 7, Rev C1. The northbridge is based on the ATI 345M IGP and the southbridge is the ALi M1533.


The list of processors that were available for the Presario 2500 match those of this Intel Mobile CPU infosheet and shows them all to be 130nm.

http://www.intel.com/products/processor/mobilepentium4/index.htm


Now, looking at the Intel S478 sheets for P4 Mobiles with HT, they are 90nm on the 533 MHz FSB.

http://www.intel.com/products/processor_number/chart/mobile_pentium4.htm


Here (finally) is the question. Can I run a 518 2.8 GHz P4 Mobile in place of my current 2.0 Ghz Celeron? I don't know what voltage my current Celeron runs at or that of the 518. I realize HT won't work as it would be installed in a system without a HT enabled chipset/BIOS. But it would give me a nice speed boost and probably also reduce heat/temp if it will work.

I'd appreciate any musings as to why this would or wouldn't work.

 

[rogue1979]

If your motherboard does indeed support a 533MHz fsb, then perhaps picking up a P4 2.8GHz on pricewatch would give you a great perfromance boost for only $65.

However, if you think the fan runs a lot now, the 2.8GHz cpu will run even hotter.

I would look for a mobile Celeron 1.8GHz which you should be able to find for $30-$40 these days. You will have break a pin off so that it will run at 2.4GHz, and make a copper shim from a penny to fit under the heatsink properly.

What will you gain? Well, the mobile Celeron is simply a P4-M with 256k L2 cache, still twice as much as a Northwood Celeron without any other difference from it's P4 big brother. It will default to 1.3v and run much cooler then a higher speed P4, which in my opinion should never have been put in a notebook, just not enough cooling.

End result, 2.4GHz which will be much faster then the 2.0GHz Celeron, it will run cooler and give you increased battery life without cooking the inside of your notebook.

 

[stevty2889]

More than likely, the 90nm chips won't work. If the chipset is old enough it doesn't support HT, it's not going to able to handle the higher power requirements of a flamethrower Precott core. Just because it supports 533mhz FSB doesn't mean al the 533mhz FSB cpu's will be supported. Stick with a northwood based P4-M.

 

[Viditor]

Originally posted by: stevty2889
More than likely, the 90nm chips won't work. If the chipset is old enough it doesn't support HT, it's not going to able to handle the higher power requirements of a flamethrower Precott core. Just because it supports 533mhz FSB doesn't mean al the 533mhz FSB cpu's will be supported. Stick with a northwood based P4-M.

Agreed...even if you could get the chip to work, that laptop wasn't designed for anywhere NEAR the TDP (Thermal Design Point) of a Prescott. You might end up with a lot of melted components...

 

[Creig]

Well, it definitely appears that my Celeron is a desktop processor running 1.475/1.525v and a straight 52.8 watt TDP. I had assumed that looking for a 90nm Prescott would yield a substantial power savings over a 130nm Northwood, but apparently that's not the case.

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

I think I'll go with your advice, stevty2889. I was originally looking at the Mobile P4 thinking all mobiles were the same, but now realize there's a Mobile P4-M as well. The Mobile P4's don't seem to help much in the way of lowering the TDP, but the P4-M is certainly what I would be looking for in the way of increased performance and decreased power consumption. And since my laptop model could be ordered with a Mobile P4 (1.2v/1.55v) I'm thinking a P4-M will drop right in (1.2v/1.3v) and lower my TDP to 20.8w/35w.

Am I correct in assuming that the P4-M is going to be a naked chip and that I'll need to shim it in order to match the processor height of my current Celeron with IHS?

 

[rogue1979]

Yes, both the P4-M and mobile Celerons are naked cores.

They are both northwoods on a .13 micron die as is the P4 2.8 I mentioned.

All should work. There is a off the wall vendor on pricewatch selling a P4-M 1.9GHz for $60.
But the 2.4GHz speed of the mobile Celeron as well as the 533MHz fsb mod will still be considerably faster.

Thing is if your notebook doesn't have true mobile P4 support, the P4 variant will default to a 12x multiplier. The mobile Celeron will default to a 18X multiplier.