Need help for PM/GM965 FSB downclock

Discussion in 'Hardware Components and Aftermarket Upgrades' started by donluca, Sep 7, 2020.

  1. donluca

    donluca Notebook Enthusiast

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    Hi everyone,

    unfortunately the original thread has been locked, so I'll try to get the more relevant information here.

    TL;DR: You can use 1066Mhz Core2Duo (and quads) on motherboards with the PM/GM965 chipset (and others) by "downclocking the FSB to 800Mhz from 1066Mhz" if the MB bios has the necessary microcodes for the new CPU.

    Original thread where all the pictures are sadly gone:
    http://forum.notebookreview.com/thr...-and-gl40-useful-info-for-pll-modders.605383/

    Actual working picture of the mod:
    http://forum.notebookreview.com/thr...-for-pll-modders.605383/page-22#post-10278099

    So it's just a matter of making a bridge between two socket holes... but there are things which are not 100% clear to me.

    In this post:
    http://forum.notebookreview.com/thr...fo-for-pll-modders.605383/page-6#post-8093213

    user @RickiBerlin stated that by isolating BSEL pins you're going to make them stuck high.
    This is something which, for me, is miles ahead better than fiddling with the socket because Core2Duo P9500 and such are ~10€ online so I'd rather just isolate or cut the pin on the CPU instead of risking damaging the socket on the motherboard.

    Can anyone confirm this?
    In order to downclock the FSB from 1066Mhz to 800Mhz do I just have to cut/isolate the BSEL 1 pin on the CPU?

    Onto another matter:

    User @remdale stated in this post:
    http://forum.notebookreview.com/thr...-for-pll-modders.605383/page-29#post-10902732

    That the whole thread was basically useless because

    This is really confusing.

    What does this mod involve? Cutting/isolating a pin? Tying it to ground or high?
    Which is the pin which needs to be "modded"? On the CPU? The motherboard? The northbridge? Which one is it?


    The solution by Remdale is really interesting because it looks like it will make the CPU work at its full 1066Mhz FSB without downclocking it, which would save the hassle of using SetFSB to get the FSB back up to its original frequency (or close to it).

    I'd be immensely grateful if someone could come here and shed some light on the topic.

    Thanks!
     
    Last edited: Sep 7, 2020
  2. remdale

    remdale Notebook Evangelist

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    I need to see schematics of your motherboard. Because BSEL1 pin can be forced by being attached to power. What you need to do is to break the connection between the north bridge and the CPU on BSEL1 pin. But you have to make sure the same pin is not forced by power on the PLL too.
    You can still use it after completing the mod to figure out the highest stable FSB frequency.
     
  3. donluca

    donluca Notebook Enthusiast

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    Thanks for chiming in.

    There are no diagrams that I know online of this notebook, it's a Packard Bell BG45-P-027.

    But I can definitely follow the trace and make the mod.

    So what I need to do is to cut the trace that goes from the northbridge to the BSEL1 pin on the cpu socket and then tie the BSEL1 pin high, right?

    EDIT: I've re-read your post carefully.
    So the first part is the classic BSEL mod, where you either jump the BSEL1 pin to Vcc (or, in this case, I can just break it and it should be stuck high).

    The second part... I've kind of lost it.
    If I just break the pin on the CPU there's going to be no connection between it and the rest of the board, so we're set on that part.

    Regarding the PLL, I guess I have to tie it to ground then? Because now, due to the broken CPU pin, it is floating, hence I should just make a bridge in a convenient spot to ground.

    Correct?
     
    Last edited: Sep 7, 2020
  4. remdale

    remdale Notebook Evangelist

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    Your platform is ASUS T32E. This is where I found it. http://vlab.su/viewtopic.php?t=3620&f=172
    Look for T32E (which is printed on your board)
    And this is the only source that has its schematics https://remont-aud.net/load/noutbuki/platforma_asus/asus_t32e_rev_2_0/313-1-0-52957?l4bViI
    Grab it from my mediafire account http://www.mediafire.com/file/f0v6tut07j575hx/ASUS_T32E_%28Packard_Bell_BG45%29.pdf/file
    Is it the same board?

    Your video core is built into the chipset. Never dealt with integrated video cores, so I'm not 100% sure if it works out. But I've heard it might not because when overcloking chipset, video core will be influenced too and who knows if it can work at much higher frequencies. But we can give it a try.
    [​IMG]

    You need to remove R2957 and move R2922 so that 1 side gets disconnected from the CPU line and the other side is still connected to the MCH line. Then just attach VCCP to the unconnected side of R2922. So the MCH will still be thinking it's operating at 800. It should suffice.
     
  5. donluca

    donluca Notebook Enthusiast

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    Wow, thank you so much!!

    I need to check if the boards match. Pretty strange as Packard Bell was part of the Acer brand, but whatever.

    I'll be away from home for a few days, I'll report back as soon as I can.

    EDIT: btw, if I just break the BSEL1 pin on the CPU, it should just work by bridging the 2957 resistor
     
  6. remdale

    remdale Notebook Evangelist

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    I'm curious if it works out. So waiting patiently. But don't install a quad.
     
  7. donluca

    donluca Notebook Enthusiast

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    My actual goal is to take advantage of the SSE4.1 instructions and lower TDP so I'll probably put in either a P8800 or a P9500.
     
  8. remdale

    remdale Notebook Evangelist

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    I would recommend you to get X9100 for better performance. But you won't be able to overclock it much because of weak VCORE power source for the CPU.
     
  9. donluca

    donluca Notebook Enthusiast

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    This notebook ain't gonna win any speed contest, it's my windows backup machine if/when things will go down burning (I mostly use Macs but sometimes I need a windows PC).

    The X9100 is 30€ on the ebay, the P8800 is 6€.
    Now it has a T5750 which runs hot and it's not that speedy, with a P8800 it's going to run Win10 nice and quick with a SSD.
    And, as a nice bonus, the battery should last longer. :p

    Not going to invest any more than that on this notebook.
     
  10. remdale

    remdale Notebook Evangelist

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    I wouldn't either:vbbiggrin:
     
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