A7N8X VDD (Chipset) Volt Mod GUIDE! [Retired sticky]

Retired Sticky

I will attempt to do a thorough guide to make this mod as easy as possible!

A BIG thanks to PMM for discovering where/how to mod the VDD on THIS board!!!

*You can ruin your board attempting this mod! I take NO responsibility if you do!

Here is a list of things you will need:
1. Soldering iron and solder
2. Hot Glue gun (optional but highly recommended!)
3. 1M ohm FIXED resistor found here
4. 1M ohm potentiometer (VR) found here
5. Wire - any kind will do, I used some old fan wire.
6. Thermal tape or just double sided will work.
7. Digital multimeter

Before you even touch the board, follow these instructions:

1. The 1M ohm potentiometer has THREE (3) solder points, we will use the CENTER point and EITHER of the other 2, it does not matter.
2. Solder the wire to one end of the 1M ohm FIXED resistor, I cut one end of the resistor short for this.
3. Solder the same wire to any of the 3 points on the potentiometer EXCEPT the center point.
4. Now we need a ground wire that will be soldered to the CENTER post of the potentiometer.
-----> At this point you should have the Fixed resistor soldered to a wire which is then soldered to one of the OUTER pins of the potentiometer. You should now also have a separate wire soldered to the CENTER pin of the potentiometer.
-----> TIP - An easy way to ground WITHOUT having to solder to the MOBO is to use an old 3 pin fan connector that plugs into one of the fan headers on the MOBO. If you use this, the BACK wire is the one for ground in the plug, the other wires can be cut off. If you don't have a 3 pin connector, no worries, you can solder the end of the ground wire to the ground pin on one of the fan headers OR, around one of the mobo mounting screw holes.

Now onto the board we go!

***UPDATE! Thanks to vmsrules, he has discoverd an ALTERNATE pin on the mobo to solder to! Use either this new one, or the old one but NOT BOTH! Everything else in the mod REMAINS the same.
Here is a pic showing the NEW PIN:



And my JUST finnished VDD mod to my NEW board using SMD Grabbers! No soldering!!!! Check it out! Works like a dream!



Take hold of the 1M ohm FIXED resistor and obviously use the side that does not have the wire soldered to it! I strongly recommend using a hot glue gun to affix the fixed resistor to the point on the board - You can solder it too if you wish but this should be reserved for people with excellent soldering skills! The point is VERY small and the resistor is VERY sensitive to heat, if you touch the resistor with the iron, the board will be borked!

While holding the fixed resistor to the point on the board, use the hot glue gun to get some glue around the area to securely hold the resistor in place. BE CAREFUL NOT to cover the VDD voltage test point with the glue!!!!! Look carefully at the picture. If you cover the test point, you can not test the VDD voltage! It is OK to get glue anywhere else, it will not harm the board. I would hold the connection for about 2 to 3 minutes while the glue dries. Be careful not to violently move the connection.



Once this is all done, there is only 1 thing left to do, ground the connection to the motherboard. Take the wire on the center post of the potentiometer and either use a fan plug like described above or solder the wire to the GROUND pin of a fan header or around any mounting hole of the mobo. Make sure you KNOW which fan pin in the header is ground, this picture should help:



What I did was I took some thermal tape which is double sided, you can use any double sided tape really, and taped it to the bottom of the potentiometer. I then stuck it on a nearby resistor so that it doesn't 'hang' off the board. Just don't tape it to the Southbridge!

Picture courtesy of impulse: PLEASE NOTE that in this picture, impulse soldered the connection, I suggest to use the glue method. This is here for reference.


Before you fire up your machine, get the potentiometer into the center position, doesn't have to be exact. With this setup, with the VR turned all the way one way you should get around 1.71V and with it turned all the way the other way you should get around 1.91V. Once you fire the rig up, get your multimeter out and test the voltage reading at the reading point. Turn the VR slowly one way, does the voltage go up or down? I have mine set to 1.85V and that is as high as I am comfortable with.

If you would like to see my board with VDD, VCORE and VDIMM mods click this link: http://www.netbetty.com/H20/asus/wholeboard.jpg

Thank you very very much, this is exactly what i have been waiting for. I will put it to good use this weekend, and let ya know the results. If ya dont hear from me.. umm, watch your back!

Great info!

This should be a Sticky!!

gj

Great info and great job, even I don't need to try it.

YOU ARE SOOOOO THE MAN!!! I've been waiting so long for a step by step on this. Thank you so much!

This needs to be a sticky.
Great info nikhsub1 your the man!

I'm curious as to why you would want to do this now that the hacked bios is out? Some people were saying it doesn't up the chipset voltage, but it sure as heck does something. Before I tried that bios I was stuck at 200 in sync mode. The board would post at 205 but not load windows. After flashing to the "uber" bios and setting the chipset voltage to 1.8 I can run 220 in sync mode. Sure did something and I don't see many people getting any higher than 230 doing the hard wired mod. BTW I don't say this to belittle your post - great work for those that want to try this out.

I guess you're one of the lucky ones. I tried the uber bios and it didn't do anything for me. People on xtremesystems measured the voltages and there was no change, so this mod is the way to go. I just ordered the supplies from radioshack. Thanks niksub!

TC said:

I'm curious as to why you would want to do this now that the hacked bios is out? Some people were saying it doesn't up the chipset voltage, but it sure as heck does something. Before I tried that bios I was stuck at 200 in sync mode. The board would post at 205 but not load windows. After flashing to the "uber" bios and setting the chipset voltage to 1.8 I can run 220 in sync mode. Sure did something and I don't see many people getting any higher than 230 doing the hard wired mod. BTW I don't say this to belittle your post - great work for those that want to try this out.

Click to expand...

TC, I used UBER, changed bios to 1.8V on the VDD then measured with a multimeter and still got 1.58V... Any chance you have a multimeter and could test YOUR board?

Yes I did measure my board. It read 1.59 before and 1.67 afterwards - even with the bios set to 1.8. So it seems that it did do something for my board, but it doesn't respond directly to that bios setting. It's 1.67 regardless of whether I select 1.7 or 1.8. It had a huge effect on my overclocking results. Before I was rock solid at 200, but couldn't load windows at 205, and couldn't even post above 207. Now I'm running rock solid at 220. My guess is the place where we're taking the reading is not the actual chipset voltage, but is somehow related to it in a second hand sort of way.

I am one of the lucky one that the A7N8X Dlx can run at 230 MHz stable (at 50% sync, since my memory cannot run at high), and 211 MHz at sync stable. The MB can even boot up XP between 233-245, but unstable and crashes.

I am tempting to measure the Vdd voltage to see what exactly it is, and probably may help to answer some of the NB/Vdd relationship to FSB.

But I only have an old moving coil multi-meter and I am not sure its input impedance is high enough so that it won't affect the voltage reading accuracy. I think its input impedance is between 50 KOhm and 100 KOhm at (1-5V range).

What voltage meter are you using (electronic or moving coil), and is the Vdd test point in your picture the Vdd power bus or just a weak signal point related to Vdd. If it is the Vdd power bus, then its impedance probably is low and it should be OK to measure it with my moving coil meter. But then I have to see how accurate can I read it.

Everyone i have seen post about the uber bios Volt trick says it doesn't work. Even on the forum where the guy hangs at. He say's it doesn't work.

It will give you a selection of more voltage, but actually does nothing. At least thats my understanding. Please someone double check that it actually does change the voltage as i am in bad need of it.

And if i can do it without having to risk my MB with the resistor mod, that would be great.

Here is some chatting between people about this bios and the voltage option on nforcehq

Solidsnaker wrote:
Hi

Sorry to report that someone from a German OC Forum said, that the "Uber Bios" Chipset Feature is a fake !


After I found out it did jack all, and that Asus have disabled the underlying code for that menu option, I have been vocal in stating that it does nothing at all.

Quote:
Try it yourself with a voltmeter. The Feature is available, but the Chipset Voltage remains the same.


We know this, it has been stated in these very forums time and time again.

Click to expand...

I use a fluke 865b to check things with. Not sure about where that resistor is in the power circuit for the chipset, if it is at all. I know I've seen all the posts about the uber bios working and not working. I was so skeptical that I didn't bother trying it for a long time. Then a friend of mine said he was having stability issues with his a7n8x at 200 in sync mode. He decided to give the uber bios a shot and he said his board went from having trouble at 200 to rock solid up to 210. He urged me to try it out - so I decided what the heck it can't hurt. I didn't expect anything, but to my great surprise my board now runs at 220 100% sync. With the old bios it would not even post at 207. Now you tell me there isn't a big difference between not posting at 207 and running rock solid looping 3dmark overnight at 220 with aggressive ram timings - the only thing I changed was flashing to the second version of the uber bios. What else can I say.

w00t!!

Thanks man

THIS-SHOULD-BE-A-STICKY

The body resistance between fingers on two different hand is somewhere between 500K - 5M Ohm (depends on individual). The resistance set up is 1-2 M Ohm (1 fix + 1 variable in series). Instead of using the resistors, I wonder whether for a quick test of just by touching one end with a finger (may be holding a metal contact) and the other hand touching ground (case), would increase the Vdd and hence the FSB.

I just measured the Vcore, Vram and Vdd:

Vcore_bios_setting = 1.65 V
Vcore_bios_reading = 1.68 V
Vcore_voltmeter = 1.63 V

Vram_bios_setting = 2.80 V
Vram_voltmeter = 2.72 V

Vdd_voltmeter = 1.48 V

The voltmeter seems to be low by about -0.05 V compared to the bios reading (which I assume is more accurate), so I think the actual Vdd on my A7N8X Dlx is 1.53 V +- 0.03 V

The NB is running at default Vdd and default HS cooling. So it looks like the key for high FSB is the chip itself and not the actual voltage level. And higher voltage always helps.

The MB is running at 211 MHz stable, and can run at 230 MHz w/ memory at 50% ASYNC (waiting for faster RAM to test SYNC). The TBred A 1800 is at 211 x 9.

Nikhsub1 ....................... this is a good guide , you should submit it to the front page .

Hey, niksub. Do you have the non-deluxe or deluxe version? Will the vcore, vdimm, and vdd chipset work on both the non-deluxe and deluxe versions? Let me know. I just ordered the supplies.

I'm not sure this mod will work on my board. The chips look differnt. Look at this pic I just took. Those 3 tiny rectangles...one of which is the soldering point looks like yours the other two dont match. Will it still work?