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celemine1Gig
05-10-2006, 06:36 PM
[page=Introduction, Parts & Overview]
Introduction

The ECS/Elitegroup NFORCE4-A939 is the cheapest nForce4 based motherboard available here in Europe. Although in contrast to the price, the overclocking options and the overall build quality of this board are both really good and far away from appearing cheap. This makes it the perfect victim for some voltmodding action.

Required parts


2x 50K trimmer potentiometers for the VCore-Mod
3x ~47K SMD 0805 resistors for the VDroop-Mod
2x 5-position dip-switches for the VID-Mod
1x 200K and 1x 10K trimmer potentiometers for the VDimm-Mod
1x 500K and 1x 50K trimmer potentiometers for the VLDT-Mod
1x 5K and 1x 500R trimmer potentiometers for the VChipset-Mod


Adjust all the potentiometers to the maximum resistance. Those are the values to start with - they are very important!

For all mods the rule is: The lower the resistance on those potentiometers, the higher the voltage. So make sure you checked if maximum resistance is set before powering up for the first time after doing the mods.

Overview
http://www.techpowerup.com/articles/140/images/overview.jpg

This should give you a rough overview of where to find the specific chips, needed for the modifications.

[page=VCore]
VCORE

Datasheet of the ISL6566 VCore-controller:

http://www.intersil.com/data/fn/FN9178.pdf

In general the VCore-Mod consists of two parts.

VCore-Mod (part1)

Let's start with the nearly common vmod-method of using the controller's feedback-pin to influence the output voltage. This mod requires you to connect a trimmer potentiometer between pin#9(FB) and Ground.

http://www.techpowerup.com/articles/140/images/vcore1.jpg

As you may see, I marked the appropriate points (pin#9 and ground). I advise you to use 2x 50K potentiometers connected in series for this mod. This way you get a total resitance of 100K, but with doubled precision in comparison to a single 100K poti. Now all you have to do is to connect the potentiometers just like shown in the picture. Decreasing resistance now means increasing volts.

VCore-Mod (part2)

The board is also suffering from a very annoying problem: The ISL6566's Overvoltage Protection (OVP) activates when a VCore option of about "+200mV" (might be a bit higher or lower in certain cases; official value is 175mV, according to the datasheet) is set in BIOS. Normally the controller should work in "VRM9.0"-mode, thus it should be no problem to supply a VCore of upto 375mV higher than the CPU's standard VCore. The problem now is that it operates in "AMD-HAMMER"-mode and all VCore-options above "+200mV" are quite useless, because the internal OVP gets tripped.
The ECS support told me, that due to the described problem, the VCOre-options higher than "+225mV" will be disabled in future BIOS releases (at the moment, BIOS 1.1g is the latest version).

The solution to this problem is simply influencing the CPU's standard VCore, which is generated through the 5 so called "VID-Pins". Those pins either carry a voltage higher than 1.2V or lower than this value. If the voltage is higher, it is interpreted as a logical 1 and if it's lower, it means a logical 0. The different voltages at those pins are the base of the VID-code, which consists of ones and zeros and determines the default voltage of the CPU, according to the operating mode of the voltage controller.

http://www.techpowerup.com/articles/140/images/vcore2.jpg

I marked the direct connections of the 5 VID-pins (yellow characters), the PULL-UP voltage (green characters) and one Ground point (blue characters).
As the name indicates, the pins marked as "Pull-Up" are used to pull the VID-pins up to a logical 1 ("high" status), while Ground is used to pull them down to a logical 0 ("low" status).

On page 11 (and following) of the ISL6566's datasheet, or the html-table below, you find the needed codes to know which pins to influence to get the desired default CPU voltage. The controller is configured to work in "AMD-HAMMER"-mode on this mainboard, so you have to rely on that table!
To perform this mod, the simplest and best way is to use 2x 5-position dip-switches and connect one side of either dip-switch to the VID-pins. That means pin number one of either 5-position switch to VID0, pin number 2 of the switch to VID1 and so on. Then connect the complete other row of pins (i.e. all 5 pins that are left on the opposite side) of one 5-position dip-switch to the green-marked PULL-UP voltage and finally the rest of the pins of the other 5-position dip-switch to Ground. Now you can set each VID-pin individually to either 1("high") or 0("low"). Of course, if you leave all the connections on the 2 5-position dip-switches "off" (unconnected), the CPU will still boot with its factory default voltage.

Example: The CPU has a default voltage of 1.4V. According to the "AMD-HAMMER"-table below, this corresponds to "0 0 1 1 0".<table class="systable">
<tr >
<th colspan="6">AMD HAMMER VOLTAGE IDENTIFICATION</th>
</tr>
<tr >
<th> VID4</th>
<th> VID3</th>
<th> VID2</th>
<th> VID1</th>
<th> VID0</th>
<th> VDAC</th>
</tr>
<tr >
<td> 1</td>
<td> 1</td>
<td> 1</td>
<td> 1</td>
<td> 1</td>
<td> Off</td>
</tr>
<tr >
<td> 1</td>
<td> 1</td>
<td> 1</td>
<td> 1</td>
<td> 0</td>
<td> 0.800</td>
</tr>
<tr >
<td> 1</td>
<td> 1</td>
<td> 1</td>
<td> 0</td>
<td> 1</td>
<td> 0.825</td>
</tr>
<tr >
<td> 1</td>
<td> 1</td>
<td> 1</td>
<td> 0</td>
<td> 0</td>
<td> 0.850</td>
</tr>
<tr >
<td> 1</td>
<td> 1</td>
<td> 0</td>
<td> 1</td>
<td> 1</td>
<td> 0.875</td>
</tr>
<tr >
<td> 1</td>
<td> 1</td>
<td> 0</td>
<td> 1</td>
<td> 0</td>
<td> 0.900</td>
</tr>
<tr >
<td> 1</td>
<td> 1</td>
<td> 0</td>
<td> 0</td>
<td> 1</td>
<td> 0.925</td>
</tr>
<tr >
<td> 1</td>
<td> 1</td>
<td> 0</td>
<td> 0</td>
<td> 0</td>
<td> 0.950</td>
</tr>
<tr >
<td> 1</td>
<td> 0</td>
<td> 1</td>
<td> 1</td>
<td> 1</td>
<td> 0.975</td>
</tr>
<tr >
<td> 1</td>
<td> 0</td>
<td> 1</td>
<td> 1</td>
<td> 0</td>
<td> 1.000</td>
</tr>
<tr >
<td> 1</td>
<td> 0</td>
<td> 1</td>
<td> 0</td>
<td> 1</td>
<td> 1.025</td>
</tr>
<tr >
<td> 1</td>
<td> 0</td>
<td> 1</td>
<td> 0</td>
<td> 0</td>
<td> 1.050</td>
</tr>
<tr >
<td> 1</td>
<td> 0</td>
<td> 0</td>
<td> 1</td>
<td> 1</td>
<td> 1.075</td>
</tr>
<tr >
<td> 1</td>
<td> 0</td>
<td> 0</td>
<td> 1</td>
<td> 0</td>
<td> 1.100</td>
</tr>
<tr >
<td> 1</td>
<td> 0</td>
<td> 0</td>
<td> 0</td>
<td> 1</td>
<td> 1.125</td>
</tr>
<tr >
<td> 1</td>
<td> 0</td>
<td> 0</td>
<td> 0</td>
<td> 0</td>
<td> 1.150</td>
</tr>
<tr >
<td> 0</td>
<td> 1</td>
<td> 1</td>
<td> 1</td>
<td> 1</td>
<td> 1.175</td>
</tr>
<tr >
<td> 0</td>
<td> 1</td>
<td> 1</td>
<td> 1</td>
<td> 0</td>
<td> 1.200</td>
</tr>
<tr >
<td> 0</td>
<td> 1</td>
<td> 1</td>
<td> 0</td>
<td> 1</td>
<td> 1.225</td>
</tr>
<tr >
<td> 0</td>
<td> 1</td>
<td> 1</td>
<td> 0</td>
<td> 0</td>
<td> 1.250</td>
</tr>
<tr >
<td> 0</td>
<td> 1</td>
<td> 0</td>
<td> 1</td>
<td> 1</td>
<td> 1.275</td>
</tr>
<tr >
<td> 0</td>
<td> 1</td>
<td> 0</td>
<td> 1</td>
<td> 0</td>
<td> 1.300</td>
</tr>
<tr >
<td> 0</td>
<td> 1</td>
<td> 0</td>
<td> 0</td>
<td> 1</td>
<td> 1.325</td>
</tr>
<tr >
<td> 0</td>
<td> 1</td>
<td> 0</td>
<td> 0</td>
<td> 0</td>
<td> 1.350</td>
</tr>
<tr >
<td> 0</td>
<td> 0</td>
<td> 1</td>
<td> 1</td>
<td> 1</td>
<td> 1.375</td>
</tr>
<tr >
<td> 0</td>
<td> 0</td>
<td> 1</td>
<td> 1</td>
<td> 0</td>
<td> 1.400</td>
</tr>
<tr >
<td> 0</td>
<td> 0</td>
<td> 1</td>
<td> 0</td>
<td> 1</td>
<td> 1.425</td>
</tr>
<tr >
<td> 0</td>
<td> 0</td>
<td> 1</td>
<td> 0</td>
<td> 0</td>
<td> 1.450</td>
</tr>
<tr >
<td> 0</td>
<td> 0</td>
<td> 0</td>
<td> 1</td>
<td> 1</td>
<td> 1.475</td>
</tr>
<tr >
<td> 0</td>
<td> 0</td>
<td> 0</td>
<td> 1</td>
<td> 0</td>
<td> 1.500</td>
</tr>
<tr >
<td> 0</td>
<td> 0</td>
<td> 0</td>
<td> 0</td>
<td> 1</td>
<td> 1.525</td>
</tr>
<tr >
<td> 0</td>
<td> 0</td>
<td> 0</td>
<td> 0</td>
<td> 0</td>
<td> 1.550</td>
</tr>
</table>

Now let's say we want to increase the default voltage to 1.55V. In order to do so, we need to change the "1", that VID1 and VID2 are set to by default, into a "0", because the VID-Code for 1.55V is "0 0 0 0 0". All we have to do in practice is to connect VID1 and VID2 to Ground and bam, we have 1.55V VCore.
Another short example:
For a default voltage of 1.1V you would need to connect VID4 to the PULL-UP voltage and VID2 to Ground.
I hope you understand the principle.

CAUTION: Only change the VID-code using the dipswitches when the system is powered OFF and never connect any VID-pin to Ground and the PULL-UP voltage at the same time!

VCore Measure
http://www.techpowerup.com/articles/140/images/vcore_measure.jpg

[page=VDimm & VLDT]

VDIMM & VLDT

Datasheet of the LM324 controller:

http://www-s.ti.com/sc/ds/lm324.pdf

This controller is responsible for Vdimm as well as VLDT.

http://www.techpowerup.com/articles/140/images/vdimm.jpg

VDIMM (left side of the LM324 according to the picture)

Connect the 200K and the 10K potentiometers in series, thus getting a total resistance of 210K. You could also only use the single 200K poti, but I like to have a bit more precision using the additional 10K poti to adjust the voltage when the changes are too high using the 200K poti alone (mostly in the lower K-Ohm-range). Finally just make the connection between pin#3 and pin#4(VCC) like shown in the picture.

VDimm and VTT Measure
http://www.techpowerup.com/articles/140/images/vdimm_measure.jpg


For the VLDT-mod you do basically the same as for VDimm. You connect 1x 500K and 1x 50K potentiometers in series, and then solder them in between pin#10 and pin#4(VCC). That's all. Just like shown in the picture above.

Important info concerning VLDT:
VLDT is directly dependant on VChipset! That means VLDT can never exceed VChipset. For example for a VLDT of 1.5V you would need to set VChipset to at least 1.55V. And so on...
The higher you set VChipset, the higher the range of adjustable VLDT voltages.

VLDT Measure
Please have a look at the next page. The picture which shows the VChipset measuring points, also shows the measuring points for VLDT as they are located directly next to eachother.


[page=VChipset & VDroop]

VChipset

Datasheet of the RT9218 controller:

http://www.richtek.com/www_en/Docs/DS9218A-03P.pdf

http://www.techpowerup.com/articles/140/images/vchipset.jpg

Take a 5K potentiometer and a 500R potentiometer and connect them in series. Finally connect those potentiometers between pin#12(FB) and Ground/GND(pin#3), just like marked in in the pic.

VChipset & VLDT Measure
http://www.techpowerup.com/articles/140/images/vchipset_measure.jpg

VDroop

http://www.techpowerup.com/articles/140/images/vdroop.jpg

This mod is used to adjust the VCore output while in idle and load until you (nearly) get a exact match. That means the lower the difference between load and idle volts, the better.
The 3 Droop-resistors are marked with RED squares. Those 3 resistors that all have the same value of 39K (marking of "393" on top) need to be exchanged for 3 equal, higher rated resistors. I used three 47K resistors (~20% increase in comparison to the default 39K), because I still had them lying around. With my CPU set to 2.6GHz, at a VCore of 1.6V, I got a Droop of ~0.009V (measured 1.648-1.657V), which I'd consider quite acceptable. Each system behaves a bit different, so you could experiment with higher or lower rated resistors to get the best effect for your individual mainboard.

Perhaps I'll add a VTT-mod if I find the time to. I actually measured VTT under load and it didn't look like it was really necessary to do the mod, but you never know. Perhaps it could help some of you.

Finished! These are all the mods that I discovered for this board. If you have any additional questions or perhaps even some additions to these mod-descritions or ideas about the modifications, then feel free to visit our discussion forums.

Warning:
All modifications are done at your own risk! I am not responsible for any damage caused by the modifications described above! Any hardware modification will definitely void your warranty! Keep that in mind.

SuperStarr
06-09-2007, 11:25 PM
Many greetings! I need help about ISL6566.
I still can't crack it at all! :D

Need to know how to find i.e. how to be sure I am find VID pins?
What to measure?

I post 2 pics bellow, one (green PCB) is Biostar NF4UL-A9A and second (blue PCB) is GA-K8NS-9-RH.
Both have ISL6566 as CPU PWM so i can with feedback vcore mod to gain only 0.15V.
Problem more for GA is that MoBo don't react on BIOS set V more than 1.425 so with current vcore, max V it can gain is 1.425V + 0.15V. I need, if it can be (simply) maked to gain 1.55V + 0.15V.
On Biostar MoBo, situation is little better, currently I can gain 1.525V (real) + 0.15V. Finally about 1.65V which is enough for Venice's.

If you can help me how to get 1.55V as default on both MoBo's I will be very grateful.

Is on Biostar model, is RN8 place for VID's, if it is, where is fifth VID?

Second quest is:
How to find resistors for vdroop?

celemine1Gig
06-10-2007, 11:51 AM
All you need to do to find the vid pin-connections, is to use a digital mutlimeter and set it to continuity test mode (test for a resistance close to zero, i.e. direct connections). Then you let one probe touch the known vid pin on the isl6566 controller and probe around for points directly connected to it on the board in that area. Or sometimes you can even follow the traces on the mobo, just by visual inspection.
Just repeat the process until you have found all 5 vid-pin connections.

BTW, the controller can supply far more voltage in VRM9 mode, but that modification would most likely need more time. AND, ~1.7V should be more than enough for todays CPUs.

SuperStarr
06-10-2007, 12:02 PM
OK, i will find it (direct connections).
If I manage right, when found VID's only have to do is short-pin him (never mind which, I understund table ;) ) to GND? If I have luck it will be near searched pin (just like on Yosur ECS or some ASRock MoBo's)?
But, what if some of that has resistor or capacitor connected?
Can it be?

Dippyskoodlez
06-10-2007, 01:00 PM
http://img.techpowerup.org/070610/Capture010.jpg

:)

Someone may find this useful!

(Pictures are pretty)
Very nice work.

edit: lol, i need to L2read. You are using a dip switch!

Wonder what other mobos use this for voltage control.. :D

celemine1Gig
06-11-2007, 06:46 PM
BTW, Superstarr, you just told me that you were confused that you couldn't find pull-up voltage points on your boards.
Pull up means that you just need a higher voltage than the reference point, to make the signal appear as a digital 1, i.e. high. Or lower than the reference for a digital 0 (low), as pull-down voltage. If I remember correctly, 1.2V was the reference point for the ISL6566. That means that you could use for example 3.3V (directly from the NT as pull up and ground as pull down. ;)

Ahh, and another little update: There is an easier VDroop mod. ;) Just didn't find it back then when I wrote the article.

d44ve
06-11-2007, 06:50 PM
screw that.... I couldnt solder that damn good

SuperStarr
06-11-2007, 07:54 PM
BTW, Superstarr, you just told me that you were confused that you couldn't find pull-up voltage points on your boards.
Pull up means that you just need a higher voltage than the reference point, to make the signal appear as a digital 1, i.e. high. Or lower than the reference for a digital 0 (low), as pull-down voltage. If I remember correctly, 1.2V was the reference point for the ISL6566. That means that you could use for example 3.3V (directly from the NT as pull up and ground as pull down. ;)

Ahh, and another little update: There is an easier VDroop mod. ;) Just didn't find it back then when I wrote the article.

OK, i Understund. If I want to Pull-Down I must solder to GND or if I want to Pull-Up I must solder it to "NT".
But, what is NT and how I can find it if it's not around VID point as on Your ECS or ARSock like I have before (see attach).
It was 5 VID points and 5 Pull-Up points in same square.
On current MoBo's (see post 2) isn't that situation. Where to search for Pull-Up points and how find it with multimer?

Solaris17
06-11-2007, 08:42 PM
sweet i have this board in another rig and was wondering how to adjust the vcore past a measly.2

celemine1Gig
06-11-2007, 08:51 PM
OK, i Understund. If I want to Pull-Down I must solder to GND or if I want to Pull-Up I must solder it to "NT".
But, what is NT and how I can find it if it's not around VID point as on Your ECS or ARSock like I have before (see attach).
It was 5 VID points and 5 Pull-Up points in same square.
On current MoBo's (see post 2) isn't that situation. Where to search for Pull-Up points and how find it with multimer?

Ooops, I'm sorry. posted on german forums at the same time NT=Netzteil=Power Supply=PSU :)
3.3V directly from the PSU.

SuperStarr
06-16-2007, 02:41 PM
Can this VID (ISL6566) mod be worked on Processor?
Look atachment (pic):
http://img526.imageshack.us/img526/7122/ocinsideah8.th.jpg (http://img526.imageshack.us/my.php?image=ocinsideah8.jpg)

celemine1Gig
06-30-2007, 03:12 PM
Can this VID (ISL6566) mod be worked on Processor?
Look atachment (pic):
http://img526.imageshack.us/img526/7122/ocinsideah8.th.jpg (http://img526.imageshack.us/my.php?image=ocinsideah8.jpg)

Sorry for the late reply. Was very busy the last weeks.

On topic: Of course this would work. You mod the CPU and not the board. And the VCore range is the one specified by AMD, so all motherboards should support it.

SuperStarr
06-30-2007, 04:01 PM
Thanks again!
This is "sufficient" mod (1.55V + 10-15% with feedback mod) for Venice's.
If I do it, I will post pics. I plain to do that with liquid silver.
Best regards!