JCLW

(Part 1 of 2)

*** DO THIS AT YOUR OWN RISK - IT'LL VOID YOUR WARRANTY ***

*** THIS MOD IS FOR INTEL TUALATIN CORES (CELERON OR PIII OR PIII-S) THAT RUN AT 1.450v, 1.500v, OR 1.475v ***

So you want to raise your default (cold boot) CPU voltage? Most motherboards use the default CPU voltage when booting, no matter what is specified in the BIOS. This can be a problem when overclocking if your processor will run at a faster speed, but only at a higher voltage. This mod will raise your default voltage to 1.650v or 1.675v.

*** Before doing this mod make sure your system runs fine at the desired voltage. Set your processor to its default speed and raise the voltage to 1.650v (but don't forget to lower it later before doing the mod). Load up your CPU (using Prime or SETI or whatever) for a few hours and check your temps.***

What we're going to do here is connect VSS to VID0, and VID1 to VID2. This will make them all "0" in the following chart, with VID3 remaining "1". Note that with a 1.45 or 1.475 chip all you have to do is connect VID1 to VID2 as VID0 is already "0".



#1: SET YOUR PROCESSOR TO ITS DEFAULT SPEED AND VOLTAGE If you have the voltage set to +0.30v in BIOS you'll get +0.30v (ie: 1.95v) after the mod when you first boot up which could damage your processor.


#2: Shut down your PC and pop the hood. Ground yourself on the case. Remove the heatsink. Remove the memory if it's close to the socket. Rotate the motherboard until you're looking at it from this orientation.


#3: With a marker identify VSS, VID0, VID1, and VID2. Draw a line from VSS to VID0, and VID1 to VID2. I won't be offended if you look at another guide to double check the position of the holes to be marked.


#4: Use a utility knife to make a notch/trench along the lines. The notch/trench keeps the wires from sticking up and preventing the CPU sitting flat in the socket. If the CPU isn't sitting flat the heatsink won't make good contact and you'll have high temps.



(Continued below)

- JW

JCLW

(Continued from above)

#5: Find some [color=red]small[/color] stranded wire. Tinned copper wire is better then copper because it is more corrosion resistant. I used the speaker wire that came with my Creative Labs Soundworks speakers.


#6: Cut off 8~9mm of wire and use a thumbtack (or anything else that's small and handy) to bend the wire into a "U". Repeat.


#7: Drop the two jumpers into the two notches/trenches you cut in step #4.


#8: Put your processor back in place. You may have to push it a little to get it in the socket but don't push too hard! If it won't go try shifting the jumpers around in the holes. If it still won't go you may have to use smaller wire to make your jumpers. Don't forget your heatsink and memory!


To undo the mod just remove the two wire jumpers.

No processors were harmed in the making of this article.

- JW

digitalwanderer

....but that guide is easy enough that even I think I can do it.

Thanks a lot, I'm gonna have to give this a try sometime real soon....

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JCLW

In case anyone wants to try different voltages:


- JW

merry

You'll make me buy one

Good guide, thanks

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Zarathustra

That's some damn fine work there! Yet another reason for me to upgrade the P3-750 in my Nostalgia box to a Tualie...

digitalwanderer

DO IT! You ain't gonna regret it, just try for one of the later Tuly revisions. Mine is a first run and can't handle 1.65v. (But no frowny, I'm happy with her. )

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JCLW

If you have a non-Tualatin capable motherboard you have to do a few other tricks in addition to a VID pin mod:

This won't work on all motherboards. You'll have better luck with decent quality boards from manufacturers who do lots of BIOS updates (ie: Asus, Abit). If you know that you can get a BIOS with Tualatin microcode then you should be good to go. Otherwise it's six of one, half a dozen of the other.

First, as always:

*** DO THIS AT YOUR OWN RISK - IT'LL VOID YOUR WARRANTY ***

*** THIS MOD IS FOR INTEL TUALATIN CORES (CELERON OR PIII OR PIII-S) THAT RUN AT 1.450v, 1.500v, OR 1.475v ***

*** FIRST GET THE LATEST BIOS FOR YOUR MOTHERBOARD ***

Isolate the following pins from the motherboard (coat with nailpolish, wrap with thin tape...):

#1 - AJ3 (RESET#2, ex GND) Failure to isolate this will cause your processor to reset every clock cycle.

#2 - AK4 (VTT_PWRGD, ex GND) Failure to isolate this will cause your CPU to do absolutely nothing.

#3 - AN3 (DYN_OE, ex GND) Failure to isolate this will cause your CPU to send a "No core or unsupported core detected" message to the computer.

In addition, the AK4 (VTT_PWRGD) pin that was just isolated needs to be connected to AK26 (PWRGOOD, ex PWRGOOD) on the chip to tell the processor that it is getting good power and can power up (thin conductive pen).

Here's a diagram showing what AK4 (VTT_PWRGD) really does. Remember it used to be grounded but now we've connected it to PWRGOOD to trick the processor into thinking that it's getting an "OK" signal from the VRM.


For a VID pin mod, it depends if you have a 1.45v or 1.475v or 1.50v processor. It will be marked on both the chip and the box when you purchase it. Get a 1.50v chip if you can, but they are harder to find.

1.45v chip: Follow the VID pin mod at the start of the post. You only need to connect VID1 to VID2, VID0 is already connected to VSS internally. Connecting them externally will have no effect, and won't harm anything.

1.475v chip: Connect VID1 to VID2 as above, but connect VID0 to VID25mv (NOT VSS) or else you may subject your core to voltages exceeding 2.1v!!!

1.50v chip: Follow the VID pin mod above.

Note that while this mod will allow a Tualatin core to run on a non-Tualatin capable motherboard, the AGTL bus will run at 1.50v instead of 1.25v (20% overvolt). On the bright side many people say this helps overclocking.

Sorry, no pics because I already have a Tualatin motherboard.

- JW

Starscream

Here's the guide I followed when I modded my CUBX - http://www.froggy.com.au/frogge/pepp...uareport1.html

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Over and outie...

digitalwanderer

...are you telling me there's a chance that I could pop a Tuly into Blue?!?!? (Blue has a CUSL2-C, I figured it was a lost cause.)

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Starscream

From what I've read the mod only works on motherboards using the 440BX chipset. So no you wouldn't be able to.

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Over and outie...

digitalwanderer

...so I'll have to steal me son's Asus P3B-F and give him the CUSL-2 is what you're saying.... Does your method work on a slocket? Wait, me slockets got a voltage regulator....how do I determine if I can use a Tuly on it???

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JCLW

It will work on both the CUSL2 series and the P3B series. I know the latest BIOSes for both have Tualatin microcode.

It doesn't work on most VIA chipset boards, but both those are intel.

If you have a slocket with a VRM for the P3B you don't have to do the VID pin mod (If you can set the voltage to 1.65v), but you still have to isolate AJ3, AK4, and AN3, as well as jumper AK4 to AK26.

- JW

JCLW

He shows AK4 to AN11 instead of AK26, which seems to work on some motherboards, but not all.

The reason he does this is AN11 (Vtt - AGTL termination voltage) runs at 1.5v and AK26 (PWRGOOD) runs at 1.8v. AK4 (VTT_PWRGD) only really wants 1.25v.

Some motherboards run without AK4 being connected at all.

The best thing would be a resistor between AK4 and AK26 but that would be hard to fit in a socket. It would be easy to solder onto the back of a slocket 'tho. Or on the back side of the motherboard I guess.

- JW

digitalwanderer

Do you mean that there's a good chance Blue CAN do the Tuly?!? Me must find some time for some serious experimenting!!!!

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Zarathustra

Find some time? Dig you have plenty! If you throw a Celery in Blue, you'll have 3 Celeron boxes. A new nickname might be in order

JCLW

DigitalWanderer: You shouldn't have to do AK4 to AK26 in the CUSL2-C.

The P3B-F will probably boot without it, but be unstable.

As a general rule, you probably don't have to do the AK4 to AK26 jumper with an i815 chipset, but you probably do with a i440BX chipset.

- JW

digitalwanderer

Hmmm...now I'm REALLY confused, but I'll take your word for it. (Methinks the confusion is do to me just waking up from a nap with the daughter and the brain is still all fuzzy.) I'm gonna try and pull Blue out tonight and see if the Tuly works in her.


Plenty of time? PLENTY OF TIME?!?!? You've never had to keep a 2 year old busy, have ya.

Speaking of 2 year olds, I'll still have my PIII800 if'n I get a new celery. Maddy turns 3 Dec 17th, so it's high time she gets her own PC too.......

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Zarathustra

Oh lord I can only imagine Dig with control of 4 separate computers

JCLW

For a slot 1 board I think it's easier to just pick up a Tualatin slocket like this one. I can get them for CDN$35 so you should be able to find them down there for US$20 or so.

- JW

WyreTheWolf

Dig... Don't you have an Athlon.....

digitalwanderer

No. I had an Altima, but I traded it in on a mini-van....

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WyreTheWolf

Time to get some Athlon Lovin...

merry

Your 1.4 Celeron @ 1.75 takes:

100*1.75/1.4=125 MHz FSB

which could mean either:

125/3=41.6 MHz or
125/4=31.2 MHz PCI frequency.

Which one is it?

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digitalwanderer

Yes.
































To be honest, I don't know. I'll poke around me bios this afternoon and check, it's a lazy T-day for me here. (My FAVORITE kind of holiday! ) Am I correct in assuming that you're about to suggest changing my PCI divider to increase me systems OCing ability? If so, could you explain the whole PCI divider thing to me a bit 'cause I've never really understood it. (Hence my never playing with it. )

In my bios I have it set to 125FSB from the 100/100/33 setting, if'n that helps any.

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JCLW

If it's 100/100/33, then 125/125/42

The PCI multiplier is the the number you multiply the FSB by to get the PCI bus speed. There is an AGP multiplier as well that works the same way. The nominal PCI bus speed is 33mhz, AGP is 66mhz.

On a 100FSB bus the PCI multiplier is usually 1/3 (100/3=33), and on a 133FSB it's usually 1/4 (133/4=33).

You're running your PCI bus at 42mhz right now, which is probably about the limit for most cards. If you could set a 1/4 multiplier you could bring it down to 31mhz which may allow you to up your processor speed.

Some times it's also refered to as the divider or ratio (1/3 multiplier = 3 divider = 1:3 ratio...)

I don't think the Asus TUSL2-C BIOS lets you run a 1/4 PCI multiplier below 133FSB. You'd need a 100/100/25 setting or the ability to pick FSBs below 133 on the 133/133/33 setting.

- JW

merry

JCLW got it covered... but I'll post this anyway.

You only have one frequency generator in the system, from which the FSB, mem bus and PCI/AGP speeds are derived, by means of multiplying/division. Those buses' speeds have to be in some relation to each other, I suppose it's a matter of synchronization, but finally this is 'decided' by the chipset design. Some choices are allowed, to accomodate various processor FSB (66, 100 or 133) and memory speed ratings (PC66, PC100, PC133) to the standard 33MHz PCI speed.

Only having one clocking system to play with, ocing the processor (upping the FSB) will also modify the mem and PCI/AGP speeds. My video card seems to give up at 36.5 MHz PCI... You are lucky!

According to this page the TUSL2-C is built around the 815 chipset, which should allow 133/133/33 (the older BX chipset is limited to 100/100/33 max.), but I couldn't find the specifics of this mobo.

Just like JCLW said, if you can get the 125MHz FSB in the 133/133/33 setting (provided you have PC133 memory, which you probably have) it is probable that you can oc some more, not being limited by the PCI/AGP devices (as you currently are).

The limits... for one thing, intel marketed the Tualatin structure up to 1.5 GHz, but then they didn't insist much on it. The chips are made in 0.13/Cu, like the P4, so you could expect to 'push' it maybe to 2 GHz...

The overclockers.com database only has three valid recordings for the 1.4GHz Celeron II, all below 1.8 GHz (the fourth one, 2.5, is obviously a mistake). However, it seems those three were done at the 100/100/33 divider setting, because the comments complain about PCI and HDD problems, but if you get the 1.4 to work at 133 FSB, you get 1.4*133/100=1.862 GHz with 'perfect' 33 MHz PCI (and IDE speed).

For the 1.3 Celeron, the best credible recording shows 1800 (the 4:4:1 stands for 133/133/33) at 1.77V, VID mod, Volcano 7+ and 41°C max. The 1.2s also seem to stop around this point (1726 with air cooling).

So it is not likely you will get a lot more, and you need proper cooling (just lookup the airflow of the Volcano 7+ and compare to your current cooler), and the guts to overvolt your processor.

But maybe it is worth trying, at least for the fun of it. Note though that in the 133 etc setting, your PCI/AGP bus being slower, you could possibly see some decrease in video performance (just a hunch) - but an increase in stability, if you need any.

Hope this helps - good luck!

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There is a war between the ones who say there is a war
and the ones who say there isn't.
~~Leonard Cohen