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View Full Version : PSU 3.3v Mod



Mikki
09-23-2003, 05:11 AM
Check out PiLsY's excellent guide here (http://www.bleedinedge.com/guides/psu_3.3v_mod/psu_3.3v_mod_pg1.html) and feel free to post your comments and questions here. :);)

pastorjay
09-23-2003, 05:29 AM
VERY cool mod PILsY... This will be helpful for many to reach the Bleedin'Edge of their board!

PJ

Hawk
09-24-2003, 06:54 AM
Very nice. . . I might just try that one out. . . . .

eva2000
09-24-2003, 08:11 AM
very nice indeed. i got 2x 550W Antec Truecontrol PSUs but the 3.3+ is already turned up to max at stock heh

Tony
09-24-2003, 01:48 PM
King of the tweakers as usual eh PiLsY...looks like an awsome way to get 3.5Vdimm from a modded P4C800..LOL

Mikki
09-24-2003, 02:23 PM
I'm dying to try this myself...;):) I've got plenty of PSU's to play with...

Tony
09-28-2003, 03:31 PM
http://www.abxzone.com/forums/showthread.php?s=&postid=554405#post554405

looks like people like the mod Matt..the word is spreading

Mikki
09-29-2003, 06:07 PM
That's great...good to see some folks using it, and good to see PiLsY getting some recognition....;) Any BE'ers try this yet? :)

eva2000
12-01-2003, 04:56 PM
Pilsy any comment on what Epox Tech says in post #5 in this thread http://www.aoaforums.com/forum/showthread.php?t=21866 ? :)

runmc
12-15-2003, 02:47 PM
The mod looks great. Your guide is full of information, and I am looking forward to trying it out.

;)

RotorHead
12-15-2003, 04:03 PM
Welcome to BE runmc :wave:

Thanks for checking out PiLsY's guide, hope it helps you out. If you got any questions just fire away.

Cheers
:beer:

ReDoCeD
03-14-2004, 12:48 PM
Thanks great guide but i will get someone else to do it for me i,m not real good with soldering irons i,d just end up wrecking a lot of motherboards :scratch:

shimmishim
05-05-2004, 01:46 PM
here is the 3.3 volt rail mod done for PastorJay

http://www.johnshim.com/mods/IMG_0727.JPG

for some strange reason all the voltage rails on the antec 550 true control real really low.

12 volt = 11.55
5 volt = 4.65
3.3 volt = 2.95

anyway the mod is done and it's currently sent to 3.01 volts... just waiting to see what mr. pj wants before i increase the voltage

Mikki
05-05-2004, 02:02 PM
Darn nice looking mod Shim....quality work there....;):)

jcniest5
05-19-2004, 07:50 PM
It's true that the Antec True550 is low on all rails.

+3.3 is at 3.20-3.23
+5.0 is at 4.84-4.87
+12 is at 11.19-11.25
-12 is at -11.69 to -11.75
-5.0 is at -4.90 to -4.93

Is there a mod that I can do to increase each rails by at least .15?

I wonder if the 5V mod for Enermax PSU also works on other brands of PSU?

shimmishim
05-19-2004, 08:09 PM
yes,

there is a 5 volt and 12 volt mod rail for the antec true series...

anything that has a vsense line you can mod.

i have an antec 430w truepower with all modded rails...

:)

i completed pastorjay's but just did his 3.3 so he could get more juice to his ram...

i wonder how it went... pj, where are you?!

zillaoc
06-22-2004, 06:15 PM
ime in the process of doing this mod to a TT 560 and a TK 480 one for a IC7 and one for a IC7-G... when ime done ill post results...:)
as of now ime messing around with a couple of chepo 350's and a 400 to get some practice and a feel for the different style's of psu's... ive already run in to a raised resistance psu and a lowered resistance style and am still working it all out in me head...
"me head is tired"
TY for the Mod PiLsY's!!!:)

zillaoc
06-23-2004, 04:49 PM
well ive completed the mod on the TT480+pfc on the IC7...
the 3.3 is at 3.59/3.60 with a multy meter @ atx header block
>>in bios and using MBM its only reading 3.46 lol...
But the mod hasent affected the vdimm at all...its still a steady 2.77v Although thats in the bios and mbm and ime unaware as to witch mosfet to test for actuall motherboard vdimm... anyone know witch one???

>> i definatly have more stability :D running 2x512 A-data pc4000 @ 280fsb 1x1... been running 2 folding at home's for about 6 hours now :rock: :wave:

ime still doing more testing and will post results when i have emm... ;)

BigStan
06-23-2004, 07:30 PM
zillaoc, help a slow Texan out. I don't understand this part. :scratch:

He is starting with the 47k pot, turning it 17 turns, but what exactly is he measuring. What is multimeter doing as he approaches 17 turns? After he takes out the 47k pot, is he saying somehow the PUS remembers where he left off from the 47k pot as he starts turning the 10k pot. Sorry, this part just really confused me.


Check the reading on your Multimeter. Rotate the barrel adjuster on the potentiometer a turn at a time, checking the reading after each half rotation. When/if you see the voltage changes then adjust slowly until you reach your desired voltage. When you reach the maximum rating of your next potentiometer, stop and swap them over and repeat. For the 22 turn linear cermet pots I recommended I have calculated the swap points below:
47k = 2.25k per turn approximately.
5 turns = 10k.
22 - 5 = 17 turns before you swap to the 10k pot.

10k = 0.5k per turn approximately.
10 turns = 5k.
22 - 10 = 12 turns before you swap to the 5k pot.

5k = 0.25k per turn approximately.
4 turns = 1k.
22 - 4 = 18 turns before you swap to the 1k pot.

1k = 50Ohms per turn approximately.

zillaoc
06-24-2004, 01:41 AM
with each pot there is a "range" of resistance that = ohms 47k=47000 ohm's max/ the 5k will only supply 5000 ohms max/ the 1k 1000 max down to 0 ohms= no resitance...
every power supply Vsense line will act a little differently...

the less ohm's or restriction that the pot is set to will = more electricty going
to the ground and not back up the Vsense line to the psu... witch will then trick the Vsense line into thinking it needs to send the 3.3v rail more juice...

the reason he says start with a 47k pot is it offers 47000ohms witch is a ton of resistance... it is safer to have more resistance then work your way slowly down to less and less resistance untill the multimeter in VDC mode reads the 3.3v going up...

i would follow his wireing instructions

>>> this is what i did:
after finding on 3 different psu's that at 20 ohms and less is where the 3.3 was responding i hook up a 10k pot and set it to 16 to 20 ohms before soldering it to anything...
"red multimeter line to center leg of pot black to outer leg/set the MM to ohms and start turning the pot adjustment screw untill in range"

after the pot is set to around there i solder it in the circuit...

then i rechecked the ohms after its in the circuit making sure i dident bump the screw or fry the pot with my shaky hands+soldering gun...

after fiinding 16.4 ohms = 3.48v approx with this psu i raised it to 3.56 by lowering the ohms with the pot adjustment screw...
after switching between ohms and VDC on the MM like 10 times to check and recheck i hooked up the psu to the mobo and fired it up...

once running i saw the bios and MBM were reading lower on the 3.3 than
what my MM had said... so i grabed the MM and tested the 3.3v line from the backside of the atx header and it was still 3.56v... so MBM and bios reading are off...

now that i know what Ohms thru the pot = the 3.56-3.6v i want.. ime off to buy
a resistor of that exact ohms... and replace the pot with the resistor so as not to worry about the pot vibrating with all the blasted tornados ime running...

zillaoc
06-24-2004, 01:58 AM
another thing i found out is that the TT 480 and 560 both have 12v and 5v adjustment pots inside the psu... my 12v was at 11.96 at the atx header to i set it to 12.06 but the 5v was fine so i left it be...
its good to know though... saves me from doing this for all the V rails... :D

BigStan
06-24-2004, 05:09 AM
OK, thanx - I've got an extra PSU sitting around. I guess I'll play with it for a while and see how I do.

Hawk
06-24-2004, 05:17 AM
:welcome: to the BE BigStan. . . :wave:

BigStan
06-24-2004, 06:10 AM
Thanx Hawk!

zillaoc
06-24-2004, 05:03 PM
thats exactly what i did... had several 350w gen psu's and got the feel for it... took me a while just to get an idea of what the hell i was doing lol...


P.S.
Glad to see ya again BigStan :D looks like theres quite a few peeps from the abit& XS forumz here W00T!!!!
and TY again for the extensive testing+results you gave me about the adata :thumb:

zillaoc
06-25-2004, 01:23 AM
heres another great guide :)
3.3v PSU mod (http://www.xtremesystems.org/forums/showthread.php?s=&threadid=37574)

BigStan
06-25-2004, 07:12 AM
zillaoc - Thanx - one the first mod he starts with a 45k r pot and lowers the resistance on the pots until he gets to a sweet spot. In the one you just posted, he just puts a 45k resistor in there and starts lowering the pot. I'm trying to understand the difference. Is it because on the second one he just splices into the sense wire and the first one he put the resistors in parallel? Is either of these methods better then the other. They seem in theory to be doing the same thing, just a different way.

zillaoc
06-25-2004, 01:09 PM
you got it thier the same mod... the 2nd mod at xs he is just mounting the
vr in a different location...
the 45k pot will offer a wider range of resistance, or lack of flow to the ground...

a 10k pot will only offer 10.000 ohms of resistance>> less resistance = more juice going to the ground... more juice going to the ground will make the 3.3 rail go up... less juice or more resistance will make the 3.3 rail go down...


this is just a example: if you set the VR at 20 ohms and that sets
the 3.3 rail to 3.4 then if you adjusted the VR to 18 ohms it should set the 3.3 rail to 3.5 or 3.6...
this is totally depending on your psu and how it responds to the VR and adjustments...

the pot is like a big door opening to the ground wire...
if you raise the resistance your closing the door = lowering the 3.3 rail
if you lower the resistance your opening the door = higher 3.3v rail

the trick is to find out how much to open the door to get the 3.3 to go up... ;)

mine seemed to go up at 16ohms or so... but every psu is different...

if anyone else has done the mod ya all should post your results and at what range your psu responded... :)

BigStan
06-29-2004, 09:06 AM
zillaoc

OK - so 3.5~3.6 is good for the 3.3 rail. What are good voltages for the 12 and 5 rails? I might try to do this over the weekend.

zillaoc
06-29-2004, 09:46 AM
ive had mine at 3.5@ the atx header 24/7 for 2 weeks or so now and all seems good and stable... mbm reads it lower but i go by the MM at the atx header...

ive read that over 3.5 24/7 inst a good thing but dont quote me on that...
its prolly hardware dependant...

and i think the biggest improvement was from teh 12v rail though...> as mine was really low now its 12.35 idle and 12 load thru mbm... and 12.55 at atx header...

BigStan
06-29-2004, 10:03 AM
So about 3.5 for the 3.3 rail, maybe 12.55 for the 12v and, maybe 5.25 forthe 5v rail. Would that be about right?

Rukee
07-02-2004, 02:18 PM
I run even a little higher then that.
3.65v, 12.9v, 5.5v.
and Hell-Fire`s Power supply mod (http://www.xtremesystems.org/forums/showthread.php?s=&threadid=37574) is a whole lot easyer to read and follow.


no-offence ment at all to the author of that tutorial! :o

PLANT
07-26-2004, 10:01 PM
Great info. :thumb: But I do have a question, why would you go about doing several vmods to your mobo when you can just increase your 3.3v rail to bump up all your voltages using that rail in one pop? I hope to gain quite a bit of stability from this mod, my 3.3v rail only reads 3.05v in MBM.

shimmishim
07-26-2004, 10:17 PM
i don't know what you're talking about...

you have to mod all 3 rails... increasing the 3.3 won't increase everything else...

just because you increae the 3.3 doesn't mean your vcore will go up or your vdimm

PLANT
07-26-2004, 10:35 PM
Pulled from the 1st page of PiLsY's guide, am I reading wrong?

Introduction

The PSU is responsible for supplying power to your entire PC. Every voltage that your motherboard sets is governed by the voltage from your power supply. This set rule also means there is another set rule. If you increase voltage on your PSU, then in the vast majority of cases you also increase voltage to your board. Everyone these days is aware of the 5v/12v tweaks available in many PSUs in the form of a potentiometer, usually internally mounted on the PCB. However, the much underestimated 3.3v line is left out.

First let's take a look at what the PSU voltage lines are used for:

PCI bus - 5v line
AGP bus - 3.3v line
Southbridge - 3.3v line
Northbridge - 3.3v line
Memory - 3.3v line*
CPU - 5v or 12v line**
Peripherals - 5v or 12v line
*Memory voltage comprises Vdimm (memory internal voltage), Vref (memory external voltage) and Vtt (memory termination voltage).
**Early boards (P3 and Athlon Thunderbird or earlier) used the 5v line for CPU voltage regulation. With increasing power needs manufacturers have recently made the switch to the more powerful and less commonly loaded 12v line.

As you can see adjusting the 3.3v line will have a vast impact on system voltages. It's important to note that adjusting the 3.3v line will usually increase system wide voltages across the board. This means you will see greater stability from the board as a whole instead of merely modifying one aspect of it. Of especially important note is the memory voltage increase. Normal vdimm mods only increase the internal voltage of the memory sticks in use. Manufacturers lay down a strict divider for all memory voltages, where Vref is 50% of vdimm and vtt. When you vdimm mod a board you are only increasing the vdimm, and are therefore inducing some instability by throwing the other voltages out of balance. A 3.3v modification will help alleviate this by raising all three voltages. This means further increase of the vdimm will yield a lower discrepancy between the three voltages. Vagp rarely yields any benefit by its raising - in most cases I would suggest leaving this at stock if adjustable in bios. However, on some P4 boards (the Epox 4PEA+ is a prime example) Vagp is linked to Northbridge and Southbridge voltage. As all 3 voltages were equal (AGP4x is 1.5v, as is stock vNB and vSB) Epox chose to save money by specifying the one voltage controller to deal with all 3 voltages. This meant that increasing Vagp on this board in particular dramatically increased the overclocking headroom of the board itself.

shimmishim
07-27-2004, 06:23 AM
Pulled from the 1st page of PiLsY's guide, am I reading wrong?

Introduction

The PSU is responsible for supplying power to your entire PC. Every voltage that your motherboard sets is governed by the voltage from your power supply. This set rule also means there is another set rule. If you increase voltage on your PSU, then in the vast majority of cases you also increase voltage to your board. Everyone these days is aware of the 5v/12v tweaks available in many PSUs in the form of a potentiometer, usually internally mounted on the PCB. However, the much underestimated 3.3v line is left out.

First let's take a look at what the PSU voltage lines are used for:

PCI bus - 5v line
AGP bus - 3.3v line
Southbridge - 3.3v line
Northbridge - 3.3v line
Memory - 3.3v line*
CPU - 5v or 12v line**
Peripherals - 5v or 12v line
*Memory voltage comprises Vdimm (memory internal voltage), Vref (memory external voltage) and Vtt (memory termination voltage).
**Early boards (P3 and Athlon Thunderbird or earlier) used the 5v line for CPU voltage regulation. With increasing power needs manufacturers have recently made the switch to the more powerful and less commonly loaded 12v line.

As you can see adjusting the 3.3v line will have a vast impact on system voltages. It's important to note that adjusting the 3.3v line will usually increase system wide voltages across the board. This means you will see greater stability from the board as a whole instead of merely modifying one aspect of it. Of especially important note is the memory voltage increase. Normal vdimm mods only increase the internal voltage of the memory sticks in use. Manufacturers lay down a strict divider for all memory voltages, where Vref is 50% of vdimm and vtt. When you vdimm mod a board you are only increasing the vdimm, and are therefore inducing some instability by throwing the other voltages out of balance. A 3.3v modification will help alleviate this by raising all three voltages. This means further increase of the vdimm will yield a lower discrepancy between the three voltages. Vagp rarely yields any benefit by its raising - in most cases I would suggest leaving this at stock if adjustable in bios. However, on some P4 boards (the Epox 4PEA+ is a prime example) Vagp is linked to Northbridge and Southbridge voltage. As all 3 voltages were equal (AGP4x is 1.5v, as is stock vNB and vSB) Epox chose to save money by specifying the one voltage controller to deal with all 3 voltages. This meant that increasing Vagp on this board in particular dramatically increased the overclocking headroom of the board itself.

increasing your 3.3 volt rail does not increase your vcore or your vdimm voltages...

just because you increase your 3.3 rail by .15 doesn't mean your vcore or vdimm will go up by that much respectfully...

you have to do vdimm and vcore mods to be able to trick the mobo into giving my juice to the vcore and vdimm and it's just not possible just by modding the 3.3 volt rail...

with the 3.3 volt rail modded you NEED VOLTAGE MODS FOR YOUR MOTHERBOARD!

also... you can't trust MBM.... buy a multimeter or if you have one around, remove your PSU, jumpstart as per se in the directions posted and measure it directly...

don't trust a software's reading of the rails

timpanogos
06-21-2005, 09:59 AM
These posts/mods are a bit dated - anything one might want/need to know about an antec 550II before diving off on some rail modifications???

Also, I've seen bits and pieces where older antec psu's had poor fan controllers and people were hard wiring the psu fans to the 12volt rails.

Any information/thoughts here appreciated.

Thanks

Chad

timpanogos
06-21-2005, 06:32 PM
Well, antec TPII 550 sense wires on 3.3, 5 and 12 - used a 2k VR on 3.3 and 5, 10k on 12. All increased voltage as resistance lowered.

Works like a champ.

DaveT
02-12-2006, 01:14 AM
I will be doingg this next downtime