[Ludek111]

Hi. I'm sorry for my english
I want to do the Voltage mod/Vmod for my Gigabyte Ep45-ud3lr.
I was readed many of thousands tutorials, and I found this forum. So, then I found "GIGABYTE GA-P35-DS3L VOLT MOD" thread. It was very helpfull, but I coudnt find vmod to my motherboard.

This board has a ISL6334 voltage regulator. After my researching i realised it's the same-one as in the ultimate Biostar Tpower i45 mboard. Then i found some service manuals, those are'nt helpful, but I interested with vmods to tpower board. And i found these pictures:

it is from modded Tpower


It is from no-modded Tpower


And these are my photos.





I realised, that i must to connect the 16th pin to the ground, using the resistor about 200kOhms, so I've done it, but it doesnt work. I have two UD3LRs, and I have some experience with OCying, and i have nine Celeren D 352@3.2 GHz, good cooling (PCFortis HE1225 and Scythe mugen 2 rev2) and 3 pentium 4 prescotts, Core2Duo E8200 and PD smithfield.

The main problem is that when i OC my E8200 (45nm) then motherboard is thinking "ohh 45nm dont hurt me", and when i put the 352s then it's thinking "oh my god, that is a cutted part of cutted pentium4, blaah" and I can set voltaga max to the 1.4 V and it is poor. But when i put 45nm E8200 then i can set voltage to the 2.0 V with no problems, but I setted max 1.8V, becouse of I dont wanna burn it.

I was thinking about some unknown secutity mechanisms (when put p4 or just more than 45 nm core, then Mo-bo is limiting voltage settings to the 1.4)...

I have seem OC possibilities of deleron D, especially when less then 90nm.

So, if anyone can help I will be very happy and maybe i overpass the 5 GHz border.


P.S.
On my E8200 i did 4.5 GHz (8xmultipler) on 1.6V using Air.

[xsuperbgx]

Looking here: http://pdf1.alldatasheet.com/datashe...SL6334CRZ.html
It looks like FB pin is #14. If Bobnova taught me anything, I would think you could measure resistance and multiply by 20. Get a 20 turn variable resistor and put the other side of the resistor to ground. I am not knowledgable enough to do any of the ocp or ovp mods without seeing pictures of someone else doing it.

[Ludek111]

Why you thing I must to connect 14 pin, and not that 16th-one?
Datasheet says that 16 is RGND (i understand it as ground regulator).

What does FB shortcut mean?

I have got slightly damaged ohmmeter/multimeter, but I'm gonna try to measure 14pin.

Edit

Between 14. pin of ISL chip and the ground is about 1,5-1kOhms.

Edit

I connected resistor to the 14. pin and to the ground, and I must say it works!!!
@xsuperbgx thx for very proper point



I started with the 500kOhms, it doesn't work, and after few Ohm-steps I setted resistor to the about 1.5Ohms, and it taked me about 0,06-0,08 Volts more (on setted default voltage in bios). When I setted 1.525 V, connecting resistor gave me about 0,11-0,18V more.


If anyone knows a better solition to solve this problem, please write.

[xsuperbgx]

You should use a variable resistor and you can adjust to whichever voltage you need.
These ones are 20 turn variable resistors. You can fine tune them to whichever resistance is needed or adjust them as you need to increase or decrease voltage.

[Ludek111]

I've done an ultimate variable resistor


If anyone wants to do it in future, here is scheme


All angle



This is very adjustable and helpful. I can set from 301,5 kOhms to 330 Ohms.

[xsuperbgx]

That will do it!

Did you get any overclock results yet?

[Ludek111]

Well, I OCed my E8200, but only to the 4,44 GHz. Those "ferrite" chokes was squeaking when I turned on resistor. This processor has only 8x multipler and I thing it needs too high bus speed, and UD3LR motherboard is let's say not made to OCing. I will try with less bus- and fsb-rate-needing cpu unit, like celeron D 352 .

I want to find the measure point of Vcore (Core Voltage), maybe anyone knows where i can found it? I can make a high resolution picture to interested persons

[xsuperbgx]

should be on the + side of the big cylinder shaped capacitors near the socket. May have to check from the back side of the board.

[Ludek111]

You mean those solid capacitors?
Hmm i don't know that is it good idea, because i've seen pictures when the multimeter minus was connected to the ground and the + connected to the one of three transistor pins(those are I thing some like power transistors [those was about 0.5-0.3 cm long]). Well I'm gonna try, but I don't know that my multimeter will tell me true value .

[Bobnova]

FB is short for FeedBack, it's the pin that the controller uses to see how much voltage it is putting out.

What I do is measure the resistence to ground and then use a trimmer that is 15-20x as much resistence, like Super said.

Glad it's working for you!

[Ludek111]

Ok, thanx. I will remember.
How can I measure correctly my cpu voltage?
Is it good idea to measure it connecting +of multimeter to the + of one of 'japanese solid capacitors' near the lga?

[xsuperbgx]

Try it and compare to software reported voltages. It wouldn't hurt to check it. Just don't short two things with your probe. (don't slip off)

[Ludek111]

So, I bought a new multimeter and I received it today. I measured Voltages.
My C2D works at the frequency of 3600 MHz (8x450). 1.35 Volts are not enough, then I set 1.4V in Bios. The Cpu-z says 1.312V and multimeter connected to the VCPU capacitor says 1.31V.

WARNING FOR THE FUTURE! If the voltage mod is connected, you can't turn on computer, because of the over voltage protections(OVP)!
You have to connect a switch.
I measured the optimal values of resistance of vmod.
The maximum safe voltage you can get using maximally 4.5 kOhms, but cpu is not stable, and it may be killed.
At 4.8kOhms and setted 1.4V cpu-z says 1.56V.
At 5.2KOhms and setted 1.4V cpu-z says 1.42V.
But you have to remember that 1.4V value in bios is inflated.
The real value is in real 1.31 as I said.

So when setted 1.4V using 5k resistor you get about 1.46V.

When I tried to set values above 4.5 Ohms, eg. less than 4.3, OVP turned off computer.

So I have to thank you for the advices, and don't use the tip above (1.5kOhm resistor) because of OVP.

Edit:
I have to remind that if you set in bios 1.6V, you will get about 1.5V, but if using VMod, you will get 1.68-1.7V.
It has not linear scale. REMEMBER and good luck!

[Ludek111]

I want to present my "score" on this motherboard, I know that it is hard to understand Polish language ;D
So if anyone want to buy lga775 mobo i recommend GA-EP45-UD3LR.
3 place on BenchIT.pl with 621 MHz of P45 chip.
Chipset Voltage I set was 1.7 V... I did it using air cooling lol.

The point of this achievement wasn't top cpu freq, but only chipset, so c2d multipler was minimum - 6x.

It's funny:
Asus Rampage
Asus Rampage
top-budget Ud3LR
DFI
DFI
Tpower

Screenshot here

[shamus_bip]

I am curious if this mod will also work on my mobo.
Mine is a EP45-DS3L and it's using the same ISL6334 controller.
I found a mod for the EP45-DS3R mobo, but it's using a different controller (ISL6336).
I know it's an old topic so if anyone should reply, it would be highly appreciated.

[Bobnova]

The same controller pin, yes. The surrounding parts may be different, so you'll need to trace the FB pin to something large enough to solder on. The resistance values may be different as well.

[shamus_bip]

So I solder one VR resistor ( 1k, 5K, 10k ??? ) connecting #14 FB pin with ground or #16 pin ?
If it's not the 16th pin, then where should I check for ground pin ?
Sorry for the noobie questions :|

[Bobnova]

1) Find the FB pin.
2) Find something directly connected to the FB pin that is large enough to solder on.
3) Measure the resistance from the FB pin to GND(ground. The metal shields on the IO ports for instance).
4) Solder a trimmer type variable resistor that is 15x-20x that resistance from the FB pin to GND. Use the middle pin and one of the end pins. Make sure you set the trimmer to have the highest possible resistance between the two pins you use. A switch between the trimmer and GND is a good idea.
5) Find a good voltage monitoring point, solder a test point onto it for checking vcore while you test the mod.

6) Boot into BIOS, check the vcore voltage with your read point.
7) Turn the switch on, the vcore should go up a little bit.
8) adjust the VR to have less resistance between the FB pin and GND. The vcore should go up.
9) Keep in mind that it's a cheap board, don't get excessive or you can expect a MOSFET to go blammo.

[Ludek111]

Buy V.Resistor 50kOhm, It has 3 "legs". Select middle one and any other, set resistance beetween them to 50 kohm, soldier first to Ground/minus, second to FB pin of voltage controller. Bobnova is master of vmod, so you better listen to him
I have to tell u one more thing. I remember, that my UD3LR has en error or something: cant turn on while Vmod is on. You have to soldier also swich (on/off). If you are absolutely shure your ISL chip, copy its name to google, open datasheet, find picture of pins and found "FB", if it's 16th pin, connect it through:
FB->VR->switch->gnd. Greetings

[shamus_bip]

Thankyou Bob for your time in explaining all that. I really appreciate it.
It is preety straighforward, but I still have some questions.

1) Any hint on where I cound search for a "good voltage monitoring point" ?
2) I am not planning to do this mod to gain higher Vcore. It is because this board has a large Vdroop. I have read on allot of topics that by doing this Hard mod , you almost eliminate Vdroop. So that is what I am looking for. My question here is that I cannot see the relation between lower resistance <-> higher vcore <-> lower Vdroop
3) I am just curious, why do you say it's a cheap board ? A more expensive board would handle this mod easier ?

LUDEK111
What do you mean by not beeing able to turn the PC on while the Vmod is on ?
I'm not planing to do this to add an "extra" button at every startup. Please give more info on that if possible.

Sry for any misspelling
Cheers`