R52 Celeron to Pentium M CPU upgrade is possible!

[underclocker]

Just wondering if anyone has upgraded an R52 that came with a Celeron M to a Pentium M, and what happened?

The Celeron M based R52's have system boards based on the 910GML chipset, which supposedly only supports 400MHz bus Celerons. I'm wondering if it properly recognizes 533MHz Dothans or 400MHz Dothans.

The same BIOS and EC images are used for the R52's with 915GM chipsets that come with Pentium M's running at 400 or 533MHz.

I know the CPU to memory transfer speed will/should stay at 400MHz, but it'd be nice to know if upgrades are possible and if SpeedStep works as it should.

[underclocker]

I picked up an R52 with Celeron 1.3. The upgrade to a Dothan 725A 1.6GHz CPU was quick and works perfectly. CPU-Z shows the voltage adjustments are correct and SpeedStep is working properly.

Note: The CPU I used was a 400MHz bus Dothan. I do not have a 533MHz bus Dothan to test with at this time, but would like to find out if those are properly set up by the BIOS. When I get one, I will test.

[underclocker]

I was able to borrow a 1.86GHz Pentium M 750 CPU from a T43 for testing purposes. This is a 533MHz core CPU.

The BIOS properly recognized the CPU and Windows booted and the CPU was properly recoginzed by XP.

CPU-Z properly identified the CPU, core speed (533MHz) and multiplier. The voltages also looked correct as reported by CPU-Z. SpeedStep worked properly, adjusting voltage and clock speed as per settings and load.

HOWEVER, the R52 cut off without warning three times during my brief (10 minute) testing. Once, when I was checking BIOS settings, and two more times while working within Windows apps. The machine would just shut off with a click.

I did not want to test further as I became concerned with damaging a borrowed CPU and/or my R52.

I placed my 1.6GHz Dothan Pentium 725A back in, and all is well again. Never had a shut down with this 400MHz bus CPU.

This brief tesing suggests that 533MHz Dothans may be properly recoginized, but are not fully supported (Officially, Intel does not support the 910GML system board with any Pentium M CPU).

I recommend further testing and testing other speed 533MHz Dothans.