Overclock Dothan using Alviso chipset notebooks

[Zap]

I was just thinking about this... the new Alviso chipset for notebooks supports 400 and 533MHz bus speeds. Typically the motherboard detects the bus speed of the CPU through two pins as I have documented here. What's to stop someone from doing this on an Alviso chipset system, unless the BIOS won't allow system to POST with such a modded chip. I've done a FSB mod on a Celeron 2GHz that was known to run at 2.66GHz on default voltage. It still runs great to this day in a Toshiba notebook that supports 400/533MHz FSB desktop P4 chips.

With the Alviso chipset, can't someone take a 1.5GHz Dothan, break off the appropriate pin and end up with a 2GHz Dothan? Granted, the CPU has to be able to handle that speed at default voltage and the mod would be permanent, but the CPU can be pre-tested on one of the desktop boards. I'm sure Intel has again graciously provided us the information in their developer site.

For even more bang-for-buck, how about a Dothan core Celeron M? Overclocked it would run faster than any Banias powered system (higher FSB, higher MHz, same cache size).

The only drawbacks I can think of would be
- Not as good battery life, speedstep clock speed 800MHz instead of 600MHz if I understand it correctly for Pentium M, and Celeron M doesn't even step down IIRC.
- Voiding warranty, mod is also permanent.
- Possibility of instability from overclock if chip can't sustain higher speed at default voltage (perhaps "wire trick" it?).
- Possibility of some BIOSes not allowing POST. The Celeron I modded/overclocked in the Toshiba notebook works great in that notebook and in an MSI 645E Max board, but did not POST in an MSI 865PE Platinum board.

Discussion/hopes/fears/speculation? Let's hear it!

 

[otispunkmeyer]

depends how the dothan has been put on the board...i always thought that alot of manufactures hard wired the cpu to their motherboards. guess not

 

[Ozz1113]

can you pm me or provide a link to how you got your Celeron to do that? I would be interested to check it out. Thanks.

 

[Mingon]

Yes in theory removing the bsel0 pin should allow this, I think it might work on the 855 motherboards as well. I have a celeron M I keep meaning to try it with.

 

[BigBadBiologist]

That would be great. I've modded some mobile CPUs to run at 200FSB and 133 FSB and most of the time it seems to work great. Unfortunately, I've also run into some BIOSes that seem to ignore the BSEL pins and just read the CPUID.

 

[Zap]

depends how the dothan has been put on the board...i always thought that alot of manufactures hard wired the cpu to their motherboards. guess not

Pentium M chips 1.3GHz and up are socketed. The slower ones that are super low voltage may be soldered. Can anyone verify?

can you pm me or provide a link to how you got your Celeron to do that? I would be interested to check it out. Thanks.

Modifying a CPU's FSB

I've modded some mobile CPUs to run at 200FSB and 133 FSB and most of the time it seems to work great. Unfortunately, I've also run into some BIOSes that seem to ignore the BSEL pins and just read the CPUID.

I guess YMMV. Like I mentioned, the Celeron 2.0 that I modded didn't POST in one board, but worked well in another board and in a notebook. I was checking out an upcoming Asus brand barebones notebook using the Alviso chipset. Unfortunately it only has integrated video. Once some "mini" PCI-E video interface becomes standard for notebooks.... would be awesome to have a killer notebook with an overclocked CPU.