Watch out for those Aopen boards! It appears they do not have multiplier adjustments.

This means the only way of underclocking a T-bred is to drop the FSB to 100. Yuk.

What I want to do is run at 166FSB with a 6x multiplier.

Yes... but be careful! One thing is that they can accept any CPU that has default Vcore between 1.1 and 1.85, and another different story is that they can override that default setting.

You can check that you can read "Adjustable CPU Vcore through BIOS" among their specifications in a lot of standard ATX Aopen Motherboards, but not with these Micro-ATX ones.

deebass -- you're right, the language they use says simply that Vcore is auto detected & set from 1.1 to 1.85V & it is not necessary to set CPU Core Voltage. So it doesn't tell us whether it can be manually set.

Obviously my last 2 AOpen board recommendations have to be confirmed by someone who has hands-on access to them.

I purchased a mATX motherboard MX46-533V a little while ago and was planning to run a P4M at 1.2v on it. The user manual states that vcore can be manually adjusted from 1.1v to 1.85v. This is not true: with a P4M it defaults to 1.6v and there is no vcore adjustment option. No more luck with normal P4.

I complained to AOpen about it and they replied that none of their mATX motherboards had adjustable vcore and this could not be changed by a bios update since the boards do not have the necessary components. In all fairness they offered to replace the board with a ATX model but that would not have been any use for me. I am considering raising an official complaint with Trading Standard for false advertising.

I kept the board though, since there does not seem to be any P4 mATX with adjustable vcore and the aopen has some good features: cpu fan speed regulated automatically in bios (3 user defined speed settings + fan turned off), passive heatsinks on more components than usual, reinforcing plate behing the cpu socket, good quality and features.

So the search'n'hunt for Micro-ATX motherboards continues...

...but I limit my search to Socket A. For Socket 478 it may be a little easier, as with a little research, at least I've found VIA VPSD P4MA Pro, based on the "illegal" and outdated VIA P4M266 chipset.

I can confirm the Abit NF7-S v2.0 Nforce 2 Ultra400 Dual DDR can undervolt through the Bios.

I have dropped my 1.65v core Xp2400+ to 1.5v and now looking at seeing how low I can go.

Range 1.1v to 2.3v

There's a guy over at OCforums running a Gigabyte GA-8IPE1000-L with a P4 2.4C OC'ed to 3.0Ghz and is running at 1.18Vcore.

In another thread (I can't find it now) he said he's run the 2.4C at default speed on LESS THAN 1 VOLT!!! on that board.

Here's the thread.

The same guy was in www.hardwarecentral.com forums running a PIII-S 1.4 GHz system with only one 5V fan a few years ago...

Cheers,

Jan

Yeah, he's a big PIII Tualatin fan. He's only recently ventured into P4-land.

Somebody should invite him here...

Jan

Newer AK79 G and D Max boards do support multiplier adjustment, but through DIP switches rather than BIOS. The switches are missing on early revision boards like mine.

For some reason my system doesn't overclock well but does undervolt nicely. Before I got the Barton I ran a 1.6v TBred B at 1.2v. I reckon the Barton will run stable at 1.25v. Also SilentBIOS is nice - I run the IGP fan at 50% and the CPU fan at 70%.

Well, you can scratch the Albatron PX865PE Pro from the list. According to it's documentation its has user adjustable Vcore from .8375V to 1.6V so I bought one to play with my 2.4C. The only Vcore adjustment that is actually available is "default", "default + .1", "default + .2V" and "default +.3". Pretty crappy range of adjustments by anyone's standards and of course no undervolting at all. Shoot.

Conacted Albatron's engineers, they said they have no plans to release a BIOS to fix this. They also say the prototypes actually did have the ability to undervolt but by the time the board made it to production it was gone. Drat.

Try Gigabyte. They should also go below 1V.

Cheers,

Jan

The only G-byte that I know for certain will go below default Vcore is the GA-8IPE1000Pro and it has a fan on the NB which will probably negate and noise-savings that I can acheive with an undervolted CPU. Plus it has the most hideous color scheme I've ever seen on a mobo. I just can't imagine putting this inside my case....

Soltek NV400-L64.

It's a single channel nForce 2 (non ultra) board with a fairly budget minded design(ie: no RAID, IEEE1394, or USB2 bracket included in a retail box). I picked it up for $76 + S&H @ Newegg with a 2500+ Barton. I've stably undervolted that CPU at 1.25V and stock speed. The board can go as low as 1.1V though. Although I've yet to try it, I would guess that it's possible to bring the 2500+ down to 1.1V with a little bit of underclocking.

Regarding a Micro ATX motherboard that has the capability to undervolt, I was searching around and found this page through Google. It shows the Biostar M7NCG MATX boards can go down as low as 1.25V. Mind you, these are the older versions (1.0~1.4), not the new M7NCG-400. I have no idea if this information is accurate or not, or if the M7NCG-400 can undervolt as well, but it is intriguing for those of you looking for an undervoltable MATX board. Good luck finding a revision 1.4 board, they seem to be kind of rare now...

Shuttle FB61 undervolts to 1.0 volts.

My new Tyan Trinity i875 (S5101) appears to undervolt. I have the ANNRF but I bet the ANF is the same way.
http://www.tyan.com/products/html/trinityi875p.html

I haven't tried to make any changes yet. The manual doesn't show any negative choices for voltages but in BIOS the choices for "CPU Voltage" are:
-125mV
-250
-375
-500
+125
+250
+375
+500
+625
+750
...yes in that order According to AIDA, my current voltage is 1.47 so the range is .97 - 2.20 if AIDA is right.

Now that's nifty!!

All you have to do is figure out your reboot issues, then try to see if it actually does undervolt. Then let me know and I'll try one myself!

The MSI K72N Delta-L undervolts quite nicely. I haven't checked out the range yet. I'll add to the post tonight when I get a chance to check it out.

Lucienrau: I have the same mobo and can't find a way to undervolt it. Overvolt, yes, but not under What bios version, etc. do you have, and am I missing something?

Thanks,
Semm

I'm using 5.3. I was having huge problems with the voltage/clock settings and the chip was getting very hot with 5.0. I installed 5.2 and that took care of the temp issues. I was having some problems with detecting the Dual channel DDR with were fixed with 5.3. I haven't had any more issues with the board so I haven't installed 5.4.


Edit: The MSI K72N Delta-L is adjustable from 1.55v to 1.8v in .25v increments.

The Abit IT7-MAX2 Rev 2.0 offers a voltage range of 1.1-1.8 in .025V increments.

I am working my way down with a P4 2.4/533, currently at 1.472V according to CPU-Z. As has been suggested here, I will run 1 hour of Prime95 at each voltage until it fails, increase the voltage by .025, and run Prime95 for 12 hours to verify stability, or increase the voltage and try again.

I have been running at 2.6GHz @ 1.536V for a couple of months, so dropping back down to 2.4 and seeing how low I can drop the voltage is a new challenge.

At 2.6, running [email protected], my CPU temp was running 53.5
At 2.4 and the lowered voltage, temps are down to 50.5 and the fan in the Seasonic Super Tornado has dropped from ~1050 to ~950 RPM. I am definitely at the point of diminishing returns since the temperature and fan speeds are both acceptably low, but of course, I have to "see what she'll do".

I'm looking around to see what voltage others are able to run the 2.4GHz P4 at, but haven't found anything yet.

David

Well damn. Sure wish I knew about that IT7 earlier.



I've had my 2.4C down to 1.25V 100% Prime95 stable on my Albatron 845PEV. I talked a little about it here.

Ralf,

That's both comforting and inspiring. From 1.5V set in the BIOS (1.475 actual), which, I did not realize, is the DEFAULT VOLTAGE for this processor , i.e. not undervolted at all, I dropped it all the way to 1.4V, fully expecting the machine to not even boot, but not only did it boot, it's running Prime95, so far so good. [Do I win some kind of award for most run-on-ing-est sentence of the day?] Guess I will bump it down another 1.0V, to 1.3V in the BIOS, ~1.275V actual, and see what happens. The 1.0V drop seems to have dropped my CPU temp another 2 degrees. At this rate my CPU will freeze at -1.0V.

It's become "academic" since the sound of my hard drives now masks the sound of the fans, so now my goal is simply to find out "how low it can go."

I was looking for a mATX board that was good for undervolting, but it seems I have to give up on those plans.

My plan at the moment is to find a board suitable for undervolting and perhaps underclocking a Barton 2500+.
The prefered board should be:
nForce2 IGP board, undervoltable to 1.1V, possible to change multiplier,
1MHz FSB adjustable, have good stability.

At the moment I have my eyes on the Abit NF7-M board.
It is not currently on the list of undervoltable motherboards, but the NF7-S 2.0 is listed (and confirmed) to go 1.1-2.3V in 0.025 steps.
I read a review of the NF7-M rev 1.2 board that could go 1.4-2.3V.

The NF7-M and NF7-S is almost identical boards, so I it seems likely that there currently is rev 2.0 board of NF7-M out there.
I would appriciate if someone can confirm both existance of NF7-M rev 2.0 (or higher) and what the lowest vcore they can handle is.

I've also been looking for an undervoltable mATX board, so I checked the M7NCG-400 out on Newegg. The first customer review says it's possible to undervolt this board.

http://secure.newegg.com/app/Custrating ... 13-138-234

I think I'm going to pick one of these up once I get the rest of my HTPC picked out.

MSI K7N2G-L (socket A, nForce 2) has the same undervolting options as its big brother, the K7N2G-ILSR, namely, 1.55-1.8v

the MSI P8T Neo (Atlon 64 - 754) is supposed to undervolt down to 1,35V.
http://www.hardtecs4u.com/reviews/2003/ ... ndex10.php

Gigabyte K8NNXP (Athlon 64 - 754): 0.8V
http://www.hardwareluxx.de/cgi-bin/ubb/ ... 000043&p=6

Gigabyte K8VNXP (Athlon 64 - 754): 0.8V
http://www.hardwareluxx.de/cgi-bin/ubb/ ... 000044&p=6

Albatron K8X800 Pro II (Athlon 64 - 754): 0.8V
http://www.hardwareluxx.de/cgi-bin/ubb/ ... 000047&p=6

Shuttle AN50R (Athlon 64 - 754): 0.8V
http://www.hardwareluxx.de/cgi-bin/ubb/ ... 000042&p=6

Gigabyte 8S655TX Ultra (SIS 655TX): 0.8V
http://www.anandtech.com/mb/showdoc.html?i=1930&p=8

Abit KV8-Max3 (Athlon 64 - 754): 0.8V
http://www.hardwareluxx.de/cgi-bin/ubb/ ... 000049&p=6

Asus SK8V (Amd - socket 940): 0.8V
http://www.planet3dnow.de/artikel/hardw ... v/11.shtml

Abit AN7 (nforce2): 1,375V
http://www.exclaim.de/tests/artikel/64_ ... -Test.html (german)

Epox 8RDA3+ (nforce2): 1,075V with 8rdavcore under Windows
http://www.silenthardware.de/forum/inde ... st&p=18382 (german)

Update on Abit boards:
Currently in the list is Abit NF7-S from 2003-03-07, but the figures are slightly wrong.

I have tested with my brand new Abit NF7-M board, but the board is exactly the same as NF7 and NF7-S. A few components are added on the NF7-M and a few others on the NF7-S, but the board, bios, power components etc are exactly the same.
The board revisiong I run is v1.21.

CPU vcore 1.1-2.3V in 0.025V steps.
DDR 2.6-2.9V in 0.1V steps (this is not really good, since some DDR can easilly take 2.5V).
Chipset 1.4-1.7V in 0.1V steps.
AGP 1.5-1.8V in 0.1V steps.

CPU Multiplier can be set from 5.5 to 14 in 0.5 steps and from 15 to 22 in 1.0 steps.

Now to the problems I have seen so far:
I got some problems with getting slow fan speeds to register. The slowest RPM that I have seen registered is 1695 RPM.

The CPU shutdown temp can be set to 60/65/70/75/Disable.
This is not very good, since most AMD processors can run a lot hotter without problems.
Edit: CPU temps seem to be fairly accurate on this board.