[M]ovie - Increase P4 memory bandwidth in 60 seconds

Howto by richbastard @ 2003-04-01

With dirt cheap memory capable of running +200Mhz showing up everywhere, it might be a good idea to give your 533FSB P4 the memory bandwidth it needs. Most of the popular 845PE Intel boards use the 4:5 FSB/MEM ratio with an 533FSB P4 inserted, hereĀ“s a trick to make it use the 3:4 divider so you can push your memory even higher!
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60 second guide


If you got lousy cooling or a bad overclocking P4, your memory is probably not maxed out using the default 4:5 front size bus / memory divider on an 845PE board. Luckely, you can trick your motherboard into thinking it's actually a 400FSB processor, making the 3:4 divider available in your BIOS.

Test rig: Gigabyte 845PE, Intel 2.4B (533FSB, stock cooler), 512mb Corsair XMS PC3500

Tools needed:
Madshrimps (c)

  • fine brush

  • needle

  • silver (or other conductive) paint

Make the 3:4 divider available in 5 steps:
  1. remove your p4 out of the mobo

  2. flip it, look at the backside and locate the 2 pins you've got to connect.

  3. Madshrimps (c)

  4. dip your fine brush in conductive paint, and paint the gap between the 2 pins.

  5. Madshrimps (c)

  6. Use your needle to remove any conductive paint that's not between the two pins.

  7. Insert it back into your mobo

Here you can see step 2 through 4 in action:

Download/Full Screen - click here

Viola, now your 533 Proc will be recognized as a 400FSB one. Upon first boot, FSB will probably be reduced from 133 to 100mhz.

Madshrimps (c)

Previously having a 4:5 divider, a 3:4 is now available. A low 150FSB now results in a nice 200mhz (400ddr) memory speed.

Madshrimps (c)

On my testrig, this mod had the following effect:
Before: P4 2.4B at 155FSB and (4:5) 194mhz mem.
After: P4 2.4B at 155FSB and (3:4) 207mhz mem.

Hope this helps you getting a little more power out of your P4. :^) Thanks to Niko@xtreme for pointing out which pins to connect!

written by richba5tard

Comments and questions can be dropped @ this thread in the forums (no regis. required)
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Comment from jmke @ 2003/04/01
Comment from calantak @ 2003/04/02
I'm running @3:4 since over 6 months now
Comment from jmke @ 2003/04/02
chipset ?
Comment from jmke @ 2003/04/02
In [M] adshrimps teneis this brief one guides of as rising the FSB of a P4. With so alone a bridge it transformareis from 400 to 533!!

To enjoy the reading Salu2

I think they misunderstood the whole thing
Comment from RichBa5tard @ 2003/04/02
Originally posted by jmke
chipset ?
Expensive 845PE mobo's (IT7-Max) can select the 3:4 divider even if it's a 533mhz proc.
Comment from jmke @ 2003/04/02
damn these spoiled brats
Comment from calantak @ 2003/04/02
Comment from BigDaddy @ 2003/04/02
That's all fine and good.

Now, why don't you show CPU Benchmarks before and after, and see how much of a performance drop the CPU gets.
Comment from jmke @ 2003/04/02
all fine and good, but this guide does show the difference in memory speed you get

of course he now can push his FSB higher and obtain the same CPU speed but have a higher memory bandwidth

maybe after this weekend I can convince the author to run some benchmarks

thanks for your input
Comment from Unregistered @ 2003/05/13
Does this change the multiplier of the CPU ?

- Sinizterguy
Comment from piotke @ 2003/05/13
Originally posted by Unregistered
Does this change the multiplier of the CPU ?

- Sinizterguy

your 133 fsb cpu will be recognized as a 100 fsb version, because of that you are able to use other dividers.
Comment from Unregistered @ 2003/06/17
Is it possible to unlock the multiplier of a P4 then?
Comment from TeuS @ 2003/06/17
nop, only some engineering samples are unlocked. with this howto you can only pump up your memory speed
Comment from Unregistered @ 2003/06/22
Try this link if they can unlock an Amd chip by using the pins on its under side some one should figure out how to do it with a p4..
Comment from Gamer @ 2003/06/22
many people have tried it, but it's not possible.
it's baked inside the chip, you can not change it from the outside.
Comment from Unregistered @ 2003/10/02
use this software to overclock p4 CPUFSB
good luck
Comment from Unregistered @ 2004/02/28
What is this software thaht allows you to overclock a p4. Also with the pin trick then dont you have to run 400mhz ram?
Comment from Gamer @ 2005/03/04