undervolting mod on barton athlon xp

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dan
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undervolting mod on barton athlon xp

Post by dan » Tue Mar 01, 2005 8:49 pm

hello,
my celeron 1100/TISU died. so i bought a gigabyte GA-7N400-SL from newegg. it is a nforce 2 ultra. it is still within 30 days to RMA.

i'm not happy b/c gigabyte omitted 2 inexcusable features
1- does not support speed fan, monitors but does not control fan RPM
2- does not support vcore adjustments

alternatively, i know it is possible to pin mod the barton clock-multiplier locked athlon xp to overclock and overvolt the cpu.

what mods do i have to do to undervolt it?

sisandra reports my athlon xp 2600 i got from newegg as a mobile though its FSB is 166. strange. it also lists its default vcore as 1.3 volts as does cpu z.

another altnerative is for me to RMA it to newegg, pay for shipping and 15% restocking fee, and get an nforce 2 motherboard that does support both fan rpm and vcore (something the 4 year old TISU did)

Tephras
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Post by Tephras » Tue Mar 01, 2005 11:41 pm

You can find all the necessary pin-mod information in the workshop of OverClocked inside. But I suppose a new motherboard will be a better alternative since you then can get one that supports fan control and you don't have to fiddle around with pin-modding.

lm
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Re: undervolting mod on barton athlon xp

Post by lm » Tue Mar 01, 2005 11:45 pm

dan wrote: what mods do i have to do to undervolt it?
Disclaimer: I do not take any responsibility of things you or anyone might do to your cpus or anything based on this text.

I cut one of the L11 bridges (there are maps of them on the net, can't remember url) of my barton 2800+ to make the default vcore sth like 0.5V lower. Then I had to use my mobos ability to overvolt (asus a7n8x deluxe 2.0) to make it run. The darn mobo only supports overvolting, no undervolting, but since the default voltage was modded way down, the "overvolt" brings it to a ok voltage.

The bridge cutting was simple: Locate the correct bridge (they are damn small), then hold a sharp knife tip over it and apply force (do be careful), until you make a hole large enough, that the specified bridge is totally split. Don't bork the surrounding bridges, which are very near!

Undoing is possible, but it is not easy! It involves painting the bridge with both unconducting and conducting paints in a very small space!

Needless to say, this WILL kill your cpus warranty.

And you shouldn't do it, if you can't do any voltage control from bios! I needed all the overvolting range I had in bios to overcome the even bigger drop in default voltage.

I know that by connecting 2 pins with wire (don't remember which ones)(easy mod, easy undo), you can make your cpu act as a mobile cpu, making the default voltage go from 1.65V to 1.45V if we are talking about barton. This might be worth a try.

JanW
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Post by JanW » Wed Mar 02, 2005 3:05 am

There is an interactive pinmod utility here. DISCLAIMER: I haven't used it myself, and don't know if the info there is accurate.

I have, however, cut L11 bridges on my Barton as indicated here using the technique lm described. Cutting the first bridge (#4 in that guide) will bring the default Vcore down by 0.4V, so you can then go up from there using the BIOS. I was less brave and cut bridges #2, #1 and #0 to bring voltage down by 0.175.

My vote goes also to sending your board back if you can. Just way less hassle.

dan
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Post by dan » Wed Mar 02, 2005 10:30 am

as far as i know, the gigabyte GA-7N400-SL does nto support any vcore adjustments, and i have the latest bios, the F3 bios, so i wouldn't be able to overvolt it either. among the inexpensive socket A motherboards, gigabyte was the only brand i recognized (i've never heard of foxcon, biostar, epox, etc.,) so i went with GA.

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