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Wasmachineman_NL
Joined: 04 Jul 2019
Posts: 988
Location: Netherlands
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 Posted: Mon Jul 13, 2020 3:52 pm Post subject: Pentium 4 Mobile Northwood pinmod? |
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Would it be possible to set the FSB to 133 via a pinmod on Northwood? That would turn my 2 GHz Pentium 4-M into the extremely rare SL6WZ!
I have a Inspiron 8200 and P4-M Northwood datasheet if needed. |
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frag_
Joined: 17 Nov 2008
Posts: 4015
Location: Estonia
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| Posted: Mon Jul 13, 2020 3:58 pm Post subject: |
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| Pinmod affects motherboard, not cpu, so if board can do 133 then yes. |
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Wasmachineman_NL
Joined: 04 Jul 2019
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| Posted: Mon Jul 13, 2020 4:24 pm Post subject: |
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| frag_ wrote: | | Pinmod affects motherboard, not cpu, so if board can do 133 then yes. |
I tried breaking off the BSEL0 pin but my M50 wouldn't boot, oh well. |
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frag_
Joined: 17 Nov 2008
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Location: Estonia
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| Posted: Mon Jul 13, 2020 4:43 pm Post subject: |
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Precision M50? A you sure it can 133?
Google says it has 845mp chipset which is 100 only. |
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Wasmachineman_NL
Joined: 04 Jul 2019
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Location: Netherlands
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| Posted: Mon Jul 13, 2020 5:37 pm Post subject: |
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| frag_ wrote: | Precision M50? A you sure it can 133?
Google says it has 845mp chipset which is 100 only. |
Oh, that explains a lot. |
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Calbris
Joined: 06 Feb 2019
Posts: 157
Location: Singapore
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| Posted: Tue Jul 14, 2020 2:17 am Post subject: Re: Pentium 4 Mobile Northwood pinmod? |
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| Wasmachineman_NL wrote: |
Would it be possible to set the FSB to 133 via a pinmod on Northwood? That would turn my 2 GHz Pentium 4-M into the extremely rare SL6WZ!
I have a Inspiron 8200 and P4-M Northwood datasheet if needed.
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Yes (in an unsupported fashion), but that's under the condition that your phase-locked loop is capable of generating a 133 MHz clock frequency. If it is not capable of generating that specific clock frequency, you're out of luck.
According to your Inspiron 8200/Precision M50's schematic, it has an Intel CK-408 PLL (IMI C9827AT). That specific PLL appears to have a 133 MHz clock setting, so I guess you're in luck.
To force the C9827AT to generate a 133 MHz clock frequency, bridge pin 54 (labeled S0 in the schematic) to pin 55 (labeled S1 in the schematic). I suggest bridging it with solder for reliability reasons.
If you value stability, you might also need to step-up the core voltage by 50mV or 100mV. In my experience, D1 steppings are far more likely to require 50mV than 100mV, so be wary of your processor's stepping revision as well.
The final part would be the DDR clock frequency problem, because I've noticed that this method of FSB overclocking seems to increase the DDR bus' speed. So if it's possible, get a pair of DDR400 RAM modules to reduce the chances of instability that could be potentially caused by the increased DDR bus speed (266 MHz x 1.33 = 354 MHz).
Good luck.
Last edited by Calbris on Wed Feb 24, 2021 7:12 am; edited 1 time in total |
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frag_
Joined: 17 Nov 2008
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Location: Estonia
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| Posted: Tue Jul 14, 2020 2:41 am Post subject: |
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Mod proposed by Calbris theoretically should work.
But the chipset itself must be able to work at increased speed. Several variants of 845 can do it, but it's still a gamble. |
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Wasmachineman_NL
Joined: 04 Jul 2019
Posts: 988
Location: Netherlands
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| Posted: Tue Jul 14, 2020 4:07 am Post subject: Re: Pentium 4 Mobile Northwood pinmod? |
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| Calbris wrote: | | Wasmachineman_NL wrote: |
Would it be possible to set the FSB to 133 via a pinmod on Northwood? That would turn my 2 GHz Pentium 4-M into the extremely rare SL6WZ!
I have a Inspiron 8200 and P4-M Northwood datasheet if needed.
|
Yes (in an unsupported fashion), but that's under the condition that your phase-locked loop is capable of generating a 133 MHz clock frequency. If it is not capable of generating that specific clock frequency, you're out of luck.
According to your Inspiron 8200/Precision M50's schematic, it has an Intel CK-408 PLL. That specific PLL appears to have a 133 MHz clock setting, so I guess you're in luck.
To force the CK-408 PLL to generate a 133 MHz clock frequency, bridge pin 54 (labeled S0 in the schematic) to pin 55 (labeled S1 in the schematic). I suggest bridging it with solder for reliability reasons.
If you value stability, you might also need to step-up the core voltage by 50mV or 100mV. In my experience, D1 steppings are far more likely to require 50mV than 100mV, so be wary of your processor's stepping revision as well.
The final part would be the DDR clock frequency problem, because I've seen that this method of FSB overclocking seems to increase the DDR bus' speed. It might be due to the 82845MP's lack of a dedicated DDR reference clock frequency, but I could be wrong. So if it's possible, get a pair of DDR400 RAM modules to reduce the chances of instability that could be potentially caused by the increased DDR bus speed (266 MHz x 1.33 = 354 MHz).
Good luck. |
Interesting, but since I can't solder i'll leave it stock for now.
Speaking of which, I do have DDR400 DIMMs from Crucial. |
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Wasmachineman_NL
Joined: 04 Jul 2019
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Location: Netherlands
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| Posted: Tue Aug 04, 2020 11:23 am Post subject: |
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| Had the board soldered, it boots but gives me a memory error. Looks like I have to find some DIMMs with unlocked EEPROMs and flash them to 354 CL3 or something. |
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Calbris
Joined: 06 Feb 2019
Posts: 157
Location: Singapore
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| Posted: Tue Aug 04, 2020 11:56 am Post subject: Re: Pentium 4 Mobile Northwood pinmod? |
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Memory error? Assuming that the FSB overclock worked, it would theoretically overclock the DDR400 modules (in DDR266 specification) to DDR354. You might want to loosen the RAM timings to DDR400 specifications (via SPDTool) and leave the speed alone, well, I don't think you can select DDR354 as it's not JEDEC-compliant.
I doubt your Crucial RAM modules are locked, mine were not locked from my experience. |
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Wasmachineman_NL
Joined: 04 Jul 2019
Posts: 988
Location: Netherlands
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| Posted: Tue Aug 04, 2020 11:58 am Post subject: Re: Pentium 4 Mobile Northwood pinmod? |
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| Calbris wrote: | Memory error? Assuming that the FSB overclock worked, it would theoretically overclock the DDR400 modules (in DDR266 specification) to DDR354. You might want to loosen the RAM timings to DDR400 specifications (via SPDTool) and leave the speed alone, well, I don't think you can select DDR354 as it's not JEDEC-compliant.
I doubt your Crucial RAM modules are locked, mine were not locked from my experience. |
Will check later. |
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