P4 Mobiles and Multipliers on the Desktop

[Crosswire3]

I have recently purchased several P4m's also known as the P4 Mobile for use with desktop boards. The first thing that you will notice is that by default the "speedstep" speed or speedstep multiplier comes into effect at only 12x making the 100FSB chip run at 1200mhz as opposed to its maximum rating being anything from 1400 to 2200. I know that most laptop mobos support these CPUs in a way that they can change the multiplier based on desired power usage/performance, but what I am interested in knowing is wether or not there is a way to mod the chip or use a software to change the multiplier in a desktop mobo. As of now the only way I can OC these babies is by upping the FSB, and what I would like to do is run the multiplier at its full potential so I oculd reach maximum speeds.

[Zebbo]

If you want change your P4's multiplier, you need lab for that(read: impossible). You need to lasercut something from the CPU. If you want change multiplier, try to get ES cpu somewhere or buy EE.

[Crosswire3]

I realize that you can't change the multiplier on a "normal" P4, however these Mobile chips are designed to have adjustable multipliers for use with the speedstep technology where the system lowers clock speed to save battery life.

[Crosswire3]

bump (i need some help quickly)

[hUMANbEATbOX]

i think there is a pin mod or something? do a search i remember a thread while back..

[Albuquerque]

The mobiles require bios support for speedstep in order to set that multiplier back where you want it. Since desktop boards have no reason to support speedstep, it's basically impossible to change it.

Throw it in a good FSB-overclocking board and beat it up that way. A 12x multiplier isn't bad when you can pull 250+fsb reliably :)

[Crosswire3]

Anyone know where this pin mod thread is...I've been looking for a while now and con't find too much on intel CPUs

[hUMANbEATbOX]

http://www.ocforums.com/showthread.php?s=&threadid=232432&highlight=bsel1

[lite12]

Crosswire3, you'll have to find the GHI# pin and ground it to a Vss pin or to the case. Look at the datasheet for your chip to locate these pins.

When the system boots it checks the signal of the GHI# pin to determine the multiplier. Signal is high by default, and the motherboard lacks the hardware capability to set it to low, so you must ground it without iscolating it.

Alternatively, you can purchase a motherboard that specifically allows changing the multiplier of Speedstep supporting chips. Mobile-compatible desktop boards or certain Asus, Abit and Gigabyte boards can do this.

-Lite

[Crosswire3]

So...by grounding this pin what will I achieve...unlocked multiplier, or default multiplier?

[Evilsizer]

you will be able to change it in the rang of the "speedstep" ie if you have a moblie 1.8 x100fsb then the highest multi will be 18x and the lowest is set at 12x...in the classifieds a guy used a 2.8 mobile p4 but he said you cant change the multi and he was using the Abit AI7 so i dont thint lite12's post is entirely correct .... you can change the multi with the abit/asus board if using a non-locked cpu (ES chips)...

[Ssetre]

Can someone show me a p4 pin map? Its BSel1 that has to be grounded out. But which pin in all 478 is BSEL1??? Any help would be most appreciated.

[Evilsizer]

sometimes it pays to be patient... but here a search i did for yall... thinking about using one of the P4-m in a HTPC since they put out less heat...

pics links:
http://homepage.ntlworld.com/ad.leach/BSEL%20mods/

another thread with a 1.8a P4-m @ 3.6ghz
http://www.abxzone.com/forums/showthread.php?t=59931&page=3&pp=15
go bietoe :drool: :attn:

[Crosswire3]

OK...we seem to have conflicting reports...is anyone sure of a pin mod (being GHI#, BSEL1, or something else) that will allow me to run the multiplier at its full speed as opposed to the 12x speedstep default, or even better unlock the CPU's multiplier alltogether?

Also...while I'm at it...Is there any harm that can come to my chips/mobos by...
1.) grounding pins (wiring to Vss pin or case)
2.) ...or by insulating them

[lite12]

So...by grounding this pin what will I achieve...unlocked multiplier, or default multiplier?
By grounding this pin it will be detected as having low signal, effectively modifying the multiplier to its higher value.

in the classifieds a guy used a 2.8 mobile p4 but he said you cant change the multi and he was using the Abit AI7 so i dont thint lite12's post is entirely correct...
Not all Abit, Asus and Gigabyte boards will do this. I only know of a handful that seem to work, and since I haven't been able to detect what part of the motherboard design allows the change in speedstep, it's a matter of trial and error.


OK...we seem to have conflicting reports...is anyone sure of a pin mod (being GHI#, BSEL1, or something else) that will allow me to run the multiplier at its full speed as opposed to the 12x speedstep default, or even better unlock the CPU's multiplier alltogether?
It will not unlock the multiplier, but as long as the GHI# pin has been grounded it will be permanently set to its higher multiplier value.

BSEL1 has nothing to do with this process. You can read the datasheets to verify the GHI# pin modification- it explains it there in detail.


Also...while I'm at it...Is there any harm that can come to my chips/mobos by...
1.) grounding pins (wiring to Vss pin or case)
2.) ...or by insulating them
It depends what method you use. I stripped the wire from a set of headphones, as they were a hair's breadth, and used this to make a small loop around the correct wires. As for the insulation, I don't know.

-Lite

[Crosswire3]

Thank you very much LITE12...;as you seem to know quite a bit about this process I will make an attempt at your solution by grounding the GHI# to a Vss pin and hope for the best.

[Crosswire3]

Well...I successfully grounded GHI#(A6) to its closest Vss(A9) via a wire-in-socket method and checked continuity on the back of the motherboard (yes...they were connected). Powered up (with much hope and anticipation) only to see the dreaded 12x multiplier show...as a matter of fact im on the very maching right now, and it it running its 12x multi just as normal :(

Well...back to the drawing board and again...if you have any new suggestions please send them my way.

[lite12]

Are you sure it's properly grounded? I've tested this method, so unless your chip is different somehow it should work.

If you'd like to raise the default FSB to 200mhz and overclock that way, you can use the BSEL1 mod. Although I found I could acheive over 270mhz with stability without using BSEL1 mod. (After 270mhz the northbridge has heating problems)

Also, if your local computer store allows you to test your CPU on it before you buy it, try the higher end Asus. They require the latest BIOS.

The chip I've tested this on is a 3.06ghz P4 mobile, hyper threading compatible, 533mhz fsb.

-Lite

[Crosswire3]

If I were to insulate the GHI# pin would or should it have a similar affect as grounding it?


now...if I were to use the BSEL1 mod would that work in a 533 max mobo?

...here's the thing...it'll only boot if the proc is 533(133)fsb max (no 800s), however through the bios it will let me OC to 666(166) and runs fine. I was just wondering if the BSEL1 mod makes the proc act as a 800fsb chip from boot-up.

[lite12]

If I were to insulate the GHI# pin would or should it have a similar affect as grounding it?

I'm not sure about that. If you have a way of reversibly insulating the pin, please try it. I would be interested in finding out if that method works.


...here's the thing...it'll only boot if the proc is 533(133)fsb max (no 800s), however through the bios it will let me OC to 666(166) and runs fine. I was just wondering if the BSEL1 mod makes the proc act as a 800fsb chip from boot-up.
It will default to 200mhz fsb, so technically yes. Before you try the BSEL1 mod, you may want to try an FSB setting of around 220-250. In my case, it won't boot at 170-180mhz, but runs stable at settings above 250mhz.

-Lite

[Ssetre]

I did the BSEL mod and I am up and running at 3.0ghz from 1.2 :). Although prime errors out like a dirty bisnitch. No matter what. I think it doesn't like the board. I've been running memtest for the better part of an hour and it hasn't hit any errors and it stresses the cpu just like prime does. It did scream when i had the chip clocked to 3.2 with the memory on loose timings and underclocked so I know it will catch errors.

[Crosswire3]

I tried some nail polish last night in order to insulate the pin(s) to no avail, and I am currently working on a solition that uses ever-so-slightly thicker wire because I think my last wire was a little to thin (rated at several .mv) and possibly wasn't getting a solid connection. I'm pretty sure this final approach will either make or break my belief in this mod, so I will let you all know how it goes.

[Crosswire3]

OK...I give up until I get my new mobo (most likely the GA-8IK1100).

[lite12]

Some of the Gigabytes will work with this, but be sure to update with the latest BIOS before you do anything else.

Keep us updated... I would suggest removing the insulation so the pin can be grounded properly...

-Lite

[Crosswire3]

Yes...I did, I double ckecked everything and the new wire was non-insulated and there was a good connection even when I shook it around a bit, so there is no doubt in my mind that it is simply my mobo.