CPU replacement: Difficult or risky?

[trharlan]

The Pentium M 2.0 GHz (760) has fallen to the point where I'm strongly considering swapping it into my T40 (2373-75U) and pulling the existing 1.5 GHz CPU.

I know the performance gain won't be huge, but I probably have a use for the old CPU.

My question, then, is whether swapping the new CPU in will present any challenges, or whether I'm missing something and it can't be done for some reason.

Thanks for your help.

[pphilipko]

If you know every step of the way, then go for it! Otherwise, I wouldn't risk damaging the computer.

[trharlan]

Well, Phil, I don't know every step of the way, but it is documented in the service book, and I'm a pretty handy guy.

Do you think the risk of damaging the computer is considerable?

[nirvana0001]

the point is: the main board in your t40 is intel 855. but P-M 760 2.0 Ghz only work with Intel 915. If you wanna replace your cpu, you gotta replace you main board first.
Please be notice that they are using different kind of CPU.
the cpu that naming 7x5 for 855 main board;
the cpu that naming 7x0 for 915 main board.

[redsb3]

Get yourself some Artic Silver 5 Thermal Paste, read the service document several times until your familiar with it and then follow it step by step. It is not overly difficult to swap a cpu. I would suggest you also go to the Artic Silver website, they have a tutorial on applying the thermal compound. It will explain exactly how to do it. Too much is as bad as not enough of this stuff but it will decrease your operating temperature
considerably. That said, its all in how comfortable you feel dismantling your thinkpad. IBM's are not the easiest to do, you have to remove quite a bit to get to it. Any remaining warranty till be VOID also, so that is a consideration as well. I question if you really require the faster cpu. I think it will only benefit you if you do photo or video work, perhaps heavy CAD work, or have maybe 15 windows open at a time, otherwise you really won't notice a difference.

[trharlan]

Thanks, Nirvana-- that means I need to use the 755 rather than the 760, then, I presume?

Red, I'll check that link.

[GomJabbar]

the point is: the main board in your t40 is intel 855. but P-M 760 2.0 Ghz only work with Intel 915. If you wanna replace your cpu, you gotta replace you main board first.
Please be notice that they are using different kind of CPU.
the cpu that naming 7x5 for 855 main board;
the cpu that naming 7x0 for 915 main board.

I haven't researched this, but you should. nirvana0001 above indicates that your choice of CPU won't work on your existing motherboard. I did a lot of research before I bought a CPU upgrade for my 600E, and along the way, I discovered that the 600, 600E, and 600X models each used a different type of CPU that was not interchangeable. You could get a range of CPU speeds that would work for each model, but they had to be the same form factor and design.

As far as replacing the CPU itself. On the 600E it went fairly smoothly. Disconnecting the ribbon cables to the keyboard and speakers was the most delicate part. Just be very careful about using antistatic precautions when handling a CPU. They are especially sensitive to damage by static electricity.

[nirvana0001]

Thanks, Nirvana-- that means I need to use the 755 rather than the 760, then, I presume?

Yes, you are right.

You could get a range of CPU speeds that would work for each model, but they had to be the same form factor and design.

I don't think so. Would you search their picture on internet? You will see they have different structure.

They are especially sensitive to damage by static electricity.

Yes, you may burn your whole thinkpad up during the process.

[nirvana0001]

The top one is Banias which you are using (7x5); the bottom one is Dothan (7x0). The right one no idea might be P-4?

http://i9.photobucket.com/albums/a80/ni ... s_back.jpg

[GomJabbar]

You could get a range of CPU speeds that would work for each model, but they had to be the same form factor and design.

I don't think so. Would you search their picture on internet? You will see they have different structure.

We may be having a problem with semantics here, I'm not sure. If you look carefully at the pin-out on the image you supplied, in the lower right hand corner of the CPU's there is a slight variation in the pin-out between the two models:

"The top one is Banias which you are using (7x5); the bottom one is Dothan (7x0)."

My point is: even though you may be able to physically plug the processor in the socket - which I doubt, these processors are different form factors and design (families: Dothan, Banias, etc.) (perhaps I'm not using exactly the right term here).

Each processor family (ie. Dothan, Banias, etc.) has a range of speeds (Ghz) that Intel offers. Generally speaking, as long as the BIOS and motherboard supports the speed, a processor of the same family or (form factor and design) can be used.

I believe that sometimes processors may have the same form factor (size, pin-out, etc.), but electrically they aren't compatible. But generally speaking, Intel does tend to change the chip design so that you can't plug the wrong processor into the motherboard.

[GomJabbar]

BTW, I wasn't trying to contradict you at all, nirvana0001. But rather, I was trying to reinforce your statement to the OP that he can't just plug in a Pentium M processor. He would have to verify that it would work, or he would have to replace the motherboard with one that would work with his chosen processor.

I was trying to drive home the point to the OP that he needed to do his homework first, before going out and buying a processor.

[FTC]

Hi,

Just a comment. You can put a Banias or a Dothan in any T4x thinkpad. They cope well with both... the only thing to consider is that T40-T42s use FSB400 (chipset 855) and T43 supports either FSB400 or FSB533 (chipset 915). This has been tested before and is documented somewhere in another thread on this same forum (using a Dothan 2M cache chip in a T40).

[darkhelmet03]

I would like to correct something uttered in this thread:

the 735, 745, 755 and 765 are Dothan 0.90 processors, _not_ Banias.

The 7x0 are simply Dothans with 533 FSB that require 915 instead of the 7x5 which are 400 FSB and require the 855 chipset.

Btw maybe sooner or later I will also be looking into swapping my 1.4 Banias with a 2 or 2.1 7x5. So I am really interested if our fellow forumer will succeed in his/her endeavour.

[GomJabbar]

I see various opinions here as to what will work. Regarding my previous comments, all I can say is that they were general in nature. I have not researched this issue. In fact I began my first post here by saying: "I haven't researched this, but you should." In other words, I am not trying to say which processor will work in any particular motherboard. The OP will have to determine that for himself.

[tehsoul]

whether 7x0 cpus work on older chipsets (400mhz fsb) is kind of irrelevant... why buy a 7x0 cpu and pay more because it can use 533mhz fsb that you wont use anyway.

[Steve007]

The Pentium M 2.0 GHz (760) has fallen to the point where I'm strongly considering swapping it into my T40 (2373-75U) and pulling the existing 1.5 GHz CPU.

I know the performance gain won't be huge, but I probably have a use for the old CPU.

My question, then, is whether swapping the new CPU in will present any challenges, or whether I'm missing something and it can't be done for some reason.

Thanks for your help.

1.5-2GHz won't be that noticeable - I wouldn't bother. It's a lot of expense & hassle for a barely noticeable speed increase. Why not opt for more RAM or get a 60GB 7200RPM drive if you want to see a massive performance increase!

[FTC]

why buy a 7x0 cpu and pay more because it can use 533mhz fsb that you wont use anyway

Hi, it's even worst than that. If it works, it will work at FSB400 but with the same multiplier, so for instance a 1.86Ghz Dothan/533 (multiplier=3.5) would work, (if at all), at 400*3.5=1400Mhz in a 855PM based lappy.

[nirvana0001]

I would like to correct something uttered in this thread:

the 735, 745, 755 and 765 are Dothan 0.90 processors, _not_ Banias.

The 7x0 are simply Dothans with 533 FSB that require 915 instead of the 7x5 which are 400 FSB and require the 855 chipset.

Btw maybe sooner or later I will also be looking into swapping my 1.4 Banias with a 2 or 2.1 7x5. So I am really interested if our fellow forumer will succeed in his/her endeavour.

I want to correct something too darkhelmet03. T40 is using Banais processor. T42 and t43 are using Dothan processor. But the processor of t42 and t43 are still different tho. processor of t42 are naming 7x5 and processor of t43 are naming 7x0. Banias also naming as 7x5. Both Dothan are 533Mhz but 855 main board only support up to 400Mhz. And both Dothan also have different "Mhz".
One more thing, the main board on T40 should be 815.
As i see, you made couple mistakes for your "correction" here.

[Navck]

And doesn't the T43 use the Sonoma platform?

[cruzlite]

darkhelmet03 quote;

I would like to correct something uttered in this thread:

the 735, 745, 755 and 765 are Dothan 0.90 processors, _not_ Banias.

--------------------------------------------------------------------------------

I have to agree w/nirvana0001 here...

I am sure the 735@1.70ghz (NO LINK)is a BANIAS...


Edit to add link;http://www.laptoplogic.com/resources/articles/42/2/1/
-------------------------------------------
Edit;I believe the info in the above the above post [I am sure the 735@1.70ghz (NO LINK)is a BANIAS...] IS INCORRECT...
My apologies...cruzlite

[cruzlite]

Bump for the link...
here it is again;

http://www.laptoplogic.com/resources/articles/42/2/1/