Processor upgrade w/ different bus speed

[tbu3]

I have an r51 (2887-58h) with a pentium m 1.5 ghz banias processor (705) with 400 mhz bus speed, 130nm architecture & 24.5w power consumption. l would like to know if I can replace it with a pentium m 1.86 (750 / 533 mhz bus speed / 90nm / 27w) without any complications.

CPU-Z shows my board with the following info:
Chipset: Intel i855GM/GME Rev. A2
Southbridge: Intel 82801DB (ICH4-M)
LCPIO: NS

Thanks.

[aaa]

Nope. The motherboard can only do 400mhz, and the 1.86 chip only has 14x multiplier. So it won't go past 1.4ghz in your board.

[tbu3]

Thanks for the info aaa. But will any pentium m with 400mhz fsb do?

[aaa]

Yes.

There have been issues with processors ending in 'a' (like 725a), they require a bit of fiddling to work if the BIOS doesn't recognize it. The BIOS on the T4x laptops don't recognize it, not sure about R5x though (since IBM actually made some R5x's that came with 725a).

[tbu3]

@ aaa - Thank you very much again for the confirmation and added info.

[tbu3]

I was able to get a Pentium M 735 (1.7 ghz). I would have wanted a 745 or 755 but thats the only one readily available at my side of the planet. Just curious though... I've read articles about overclocking pentium m's using the pin mod technique and would like to know if it can be applied to my 855 chipset? If not are there other overclocking techniques that may be effectively applied to my board and processor? Thanks in advance.

[aaa]

There are software like clockgen and setfsb, for about 10% increase.

The pinmod requires 533 support from the board. So the easy way of doing it is not possible. However, a forum member here (cithrix) was able to force his 400 board to do 533 (33% overlcock of everything, cpu, ram, etc).

[tbu3]

Woah! He must have done some really hardcore modding. I've been searching the web for weeks and couldn't find a tutorial on the thing. I'll try to get in touch with cithrix and ask about his hack. Thanks again.

[aaa]

Just search for posts he made here. I think he just modified a resistor or two.

[Peter_Peril]

Woah! He must have done some really hardcore modding. I've been searching the web for weeks and couldn't find a tutorial on the thing. I'll try to get in touch with cithrix and ask about his hack. Thanks again.

Bump. Hey let us know how you overcome the fan issues

[tbu3]

I sent cithrix a pm. I will await his response and post the results... if I happen to find the guts to try what he did. LOL.

[aaa]

It's for R50, but it might help:
http://forum.thinkpads.com/viewtopic.ph ... 119#409119