BSEL Mod on a socket P explained with photos

[Daytona 955i]

Aha... P18 of the datasheet talks of Enhanced Intel Speedstep Technology...

Voltage and frequency selection is software-controlled by writing to processor MSRs:

--If the target frequency is higher than the current frequency, Vcc is ramped up in steps by placing new values on the VID pins, and the PLL then locks to the new frequency.

--If the target frequency is lower than the current frequency, the PLL locks to the new frequency, and the Vcc is changed through the VID pin mechanism.

There we go. If I remove the pins and hardwire the VID pins to Vss(ground/low-level signal) and Vcc(high-level signal), it should always remain in the power state set by the configuration of VID0:6. Excellent. I'll snip the pins off tonight and give it a go.

I tend to think leaving them open-circuit for low-level would still work, but it doesn't really seem worth bothering with. It's a pain to strip and rebuild with each test case...

Edit - attached images showing hard-wires for 0.90v, 0.95v, 1.00v & 1.10v. No promises, not tested, your own risk, etc.

[Daytona 955i]

Just rebuilt. Hard-wired for 1.00v after snipping the pins from the CPU(using a retractable/neverending pencil is great for this).

System is up and running, appears stable(though not conclusive yet). It's been running for 15 minutes under full-load, and oscillates between no fan at all, to silent fan mode. CPU temperature according to RMClock's monitoring section goes from - under full load - 52.5C(when the fan cuts off) to 62C(when the silent fan-mode starts).

Pretty good, overall. Am tempted to pull the CPU and go for 0.9v, see how it goes... but I run the risk of mucking it up. I've reached my goal, and shouldn't tinker further...

No core voltage measurements. I didn't want to disturb the CPU if possible, so opted to run it without a battery, with my hand on the AC adapter lead to yank it out quickly if anything seemed wrong...

Edit - decided to leave it at 1.00v, rather than try and get it lower. Currently have the machine running under load to check stability...

Picture shows the pins to remove if wanting to manually set the CPU voltage... Sorry about the quality, I had a hard time getting the pin legs to focus on my phone!

[naton]

Edit - decided to leave it at 1.00v, rather than try and get it lower. Currently have the machine running under load to check stability...

It's a wise decition.
I have to say that you did a very good job here

[Daytona 955i]

Been under 100% load now for some 14 hours, seems fine. Am tempted to go for 0.95 or even 0.9v... but I'll be sensible and leave it.

Cheers for all your advice.

[ezra_bujang]

does it work with acer aspire 3680, intel celeron m410@1.46Ghz?

[naton]

does it work with acer aspire 3680, intel celeron m410@1.46Ghz?

What's your chipset? is it the intel i940 or i943?

If it's the i940 the BSEL mod won't work.

If it's the i943 or i945 it will work. You can try the BSEL mod from 133Mhz to 166Mhz. This will allow your Celeron M410 to run at 1.83Ghz. The details of the mod are in the first page

[ezra_bujang]

What's your chipset? is it the intel i940 or i943?

If it's the i940 the BSEL mod won't work.

If it's the i943 or i945 it will work. You can try the BSEL mod from 133Mhz to 166Mhz. This will allow your Celeron M410 to run at 1.83Ghz. The details of the mod are in the first page

unfortunately, mine is i940..

[naton]

unfortunately, mine is i940..

you're prety much out of luck. You can't even upgrade to a dual core CPU

You can still gain a lot of performance by upgrading to a Celeron M450 (2Ghz) or a Core Solo T1350

[User Retired 2]

unfortunately, mine is i940..

Since the BSEL mod on the CPU won't work, try a FSLx PLL pinmod.

[naton]

Since the BSEL mod on the CPU won't work, try a FSLx PLL pinmod.

Would that work on a chipset that doesn't support anything over 133Mhz FSB?