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Antinomy's Low Clock Challenge


Leeghoofd

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You say you want a revolution?

Do you see anything strange over here?

Spoiler

TL;DR:
So all you need to do is solder a jumper from AL2 pin to Ground.

So here's the explanation. CPUs starting from P3 Mobile have different performance states. P4 have several technologies for power-saving (C1E, EIST) but I'll talk about something different. Thermal monitor. The one that prevents CPU from damage in case of overheat. The older TM1 is known as throttling when a CPU skips a percent of clocks. The newer one, TM2 drops the multiplier to minimum possible for given core and voltage to a lower state.
image.png.f2a78b0cde813a35d940310d6f59622e.png

image.png.5d8ca3c21830bb56067dfa94cfb07622.png

So we can see that the PROCHOT# signal triggers a multiplier drop but the signal is present only in a high temperature situation... or not?

image.png.101f7040f23f86ec4db08da340fdf431.png

So after all the PROCHOT# signal not only works as an output letting the system aware of a CPU overheat condition but also as an input to be aware of a system (VRM, etc) overheat condition. Once PROCHOT# is triggered (pulled low), the CPU uses it's safety mechanisms - TM2 or TM1 (whichever is enabled by BIOS or software). If it's TM2 it'll drop multiplier to its minimum, hence, 14x for Prescott.
This trick works on all LGA775 CPUs even without C1E like Celeron 3xx, 4xx and so on.

Now as you see, 478 adapters are pretty much useless for this competition. ?

snaphsot0003.png

Edited by Antinomy
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9 hours ago, Antinomy said:

You say you want a revolution?

Do you see anything strange over here?

  Reveal hidden contents

TL;DR:
So all you need to do is solder a jumper from AL2 pin to Ground.

So here's the explanation. CPUs starting from P3 Mobile have different performance states. P4 have several technologies for power-saving (C1E, EIST) but I'll talk about something different. Thermal monitor. The one that prevents CPU from damage in case of overheat. The older TM1 is known as throttling when a CPU skips a percent of clocks. The newer one, TM2 drops the multiplier to minimum possible for given core and voltage to a lower state.
image.png.f2a78b0cde813a35d940310d6f59622e.png

image.png.5d8ca3c21830bb56067dfa94cfb07622.png

So we can see that the PROCHOT# signal triggers a multiplier drop but the signal is present only in a high temperature situation... or not?

image.png.101f7040f23f86ec4db08da340fdf431.png

So after all the PROCHOT# signal not only works as an output letting the system aware of a CPU overheat condition but also as an input to be aware of a system (VRM, etc) overheat condition. Once PROCHOT# is triggered (pulled low), the CPU uses it's safety mechanisms - TM2 or TM1 (whichever is enabled by BIOS or software). If it's TM2 it'll drop multiplier to its minimum, hence, 14x for Prescott.
This trick works on all LGA775 CPUs even without C1E like Celeron 3xx, 4xx and so on.

Now as you see, 478 adapters are pretty much useless for this competition. ?

snaphsot0003.png

It seems this could also be possible without any hard mods. Using the Intel Integrator Toolkit & D975XBX2KR, the multiplier can be forced to 14x through BIOS editing. I have just tested it with success:

EDIT: Nevermind, in-OS it is still 20x multi...

IMG_20221101_180758007.jpg

IMG_20221101_180806216_HDR.jpg

Edited by MachineLearning
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4 minutes ago, Antinomy said:

Because this BIOS options works with EIST and it's blocked on Celeron CPUs. BTW, any interesting timings available through Intel Integrator toolkit on your Bad Axe?

That makes sense. :)

Unfortunately no, nothing unusual. Same RAM timings available as usual. I can PM screenshots if you're interested. Also have details on the board/other changes here: https://warp9-systems.proboards.com/thread/1838/intel-bad-axe-d975xbx2-kr At the bottom is a changelog, including all timings I could alter. And a link to a .Zip including ITK 4.0.x, .ITW file, .BIO, everything necessary.

Edited by MachineLearning
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Awesome i searched datasheet for something like this cause i knew 14x multi exists, just wasn't sure how to do it... Guess i just suck at finding the things i want first time around ?

Anyways this will be so much better now as any celly will do, no need for unicorn hunting...

Edited by TAGG
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