ATI 4850/4870 voltmod thread

[wesleyclark]

yep, I make sure mine turn the same as each other.

Alright. Thanks for the info. That helps clear up a bit for me.

Also, could someone explain to me jason4207's use of the molex plug in his mod found HERE.
I think he is using it as a switch to enable/disable the mods, but i am unsure of how it works unless he has the female adapter with cables connecting both the vgpu and vmem to the ground.

And also, where is a good place online that you get your Trimpots from?

[jason4207]

I like to set them so that clockwise results in the resistance lowering...which results in the voltage rising. It's just like turning up the stereo volume!

[jason4207]

Alright. Thanks for the info. That helps clear up a bit for me.

Also, could someone explain to me jason4207's use of the molex plug in his mod found HERE.
I think he is using it as a switch to enable/disable the mods, but i am unsure of how it works unless he has the female adapter with cables connecting both the vgpu and vmem to the ground.

And also, where is a good place online that you get your Trimpots from?

That molex is a convenient way to measure the vGPU, and vMEM. I simply stick the black probe into the GND molex hole, and the red probe into the vGPU molex hole or vMem hole to measure the respective voltage.

Like this:



I usually order from Mouse Electronics, but i like the Allied Electronics website better. DigiKey is another one.

[wesleyclark]

That molex is a convenient way to measure the vGPU, and vMEM. I simply stick the black probe into the GND molex hole, and the red probe into the vGPU molex hole or vMem hole to measure the respective voltage.

hey, that's a pretty good idea. I was only going to add a simple slider switch to disable the mods if i needed to, but now i might also add a molex, or something similar to get the voltage readout function too!

And i hope you didn't take that above pic just for me. Haha

[jason4207]

hey, that's a pretty good idea. I was only going to add a simple slider switch to disable the mods if i needed to, but now i might also add a molex, or something similar to get the voltage readout function too!

And i hope you didn't take that above pic just for me. Haha

It's been stored on Imageshack for a while.

You'll also notice that the blue VR's are inserted into the 3-pin fan connectors. Simply pull the VR out, and you're back to stock voltages.

[wesleyclark]

It's been stored on Imageshack for a while.

You'll also notice that the blue VR's are inserted into the 3-pin fan connectors. Simply pull the VR out, and you're back to stock voltages.

haha, i guess that works too.

so, just to make sure i get this right. Im trying to make things as clear cut for me, and any one else new to this. I've made a clean schematic labeling everything that needs to be done, and all of the measurement points. Can you let me know if i am missing anything or messed up on anything.

The is the main area.




The full image is available HERE.
The base picture i used i obtained from TechPowerUp from THIS article.

[eddieobscurant]

I'm in about the same position as wesleyclark, which is i'm about to mod my first card (4850)!!! And i have a few questions. First jason4207, how can you put the middle pin of the blue vr into the fan connector since it isn't in the same line with the other two, and second do i have to use these very small cables (which i don't know how they called and where to find them) you used in your mod or i could use the cables that the fan connector had?

Is the yellow spot that wesleyclark posted right? cause i have read that the right spot is this one

or maybe both can be used?

I would like to thank everyone for the help and the info you provide us.

[adpr_02]

I am also curious. That would make my VGPU mod much much easier..

Edit. Also, I am curious. What is the max Voltage I shoudl apply for the memory. I am at 2.07 right now at 1100mhz using the stock cooler. Thanks.

[Vlad_13]

Hi, 1st post getting Asus 4850 in a mail tomorrow, planing to put Maze 4 on it and OC it to 800.

Quick question, what voltage do you need for 4850 GPU to reach stable 800MHz. Also is it possible to reach 800 MHz trough BIOS only or Vmod is needed.

Thanks.

[wesleyclark]

Is the yellow spot that wesleyclark posted right?
or maybe both can be used?

I think both can be used. jason4207 uses the spot that you pointed out, and jimmyz uses the spot that i pointed out. I can go add the other one to the image now.

[Clemmaster]

That makes sense. So you could use either pin, it just depends on which way you want to turn?

Yes but cut it before soldering else you could start with your resistance @ 0 if you solder the wrong one

[zaraza]

who has done the pencil mod? how safe is it? just a regular # 2?

is there a way to check voltage in windows? i dont have a multimeter lol

[wesleyclark]

do i have to use these very small cables (which i don't know how they called and where to find them) you used in your mod or i could use the cables that the fan connector had?.

You could use the cables that came off of the fan connector. You generally want a small cable though, so that it wont contact any other points besides the ones you need.

who has done the pencil mod? how safe is it? just a regular # 2?
is there a way to check voltage in windows? i dont have a multimeter lol

I am unaware of any way to check graphic card voltages in windows. If you do not have a multimeter i would not try this mod. As you may end up damaging your card if you do not have the right resistance. But yes, just a normal #2 pencil will work.

[zaraza]

what kind of multimeter do i need? I want to try this mod, i can borrow one from a friend. And do i check the voltage when the card is off? or on? lol. Bear with me plz

[wesleyclark]

what kind of multimeter do i need? I want to try this mod, i can borrow one from a friend. And do i check the voltage when the card is off? or on? lol. Bear with me plz

Just a standard multimeter that can check resistance and voltages. You can get one from your local radioshack for around $20. You can check the resistance of your pencil mod while the card is off and see if it is in the correct range. But you can only check the voltages while the card is on. When you check the voltages, make sure you check them very soon after turning it on. Otherwise you may be running them to high and risk burning out your card.

[jason4207]

haha, i guess that works too.

so, just to make sure i get this right. Im trying to make things as clear cut for me, and any one else new to this. I've made a clean schematic labeling everything that needs to be done, and all of the measurement points. Can you let me know if i am missing anything or messed up on anything.

The is the main area.




The full image is available HERE.
The base picture i used i obtained from TechPowerUp from THIS article.

I think you have the wrong spot. You can see the trace line on the board if you look closely. Anywhere along the trace line is perfectly fine. I actually bridged two points along the line for a stronger connection. All points along the trace are electrically the same point.

It's a good idea to take resistance measurements before, during, and after you install the mods. Then you can see if your readings are matching up w/ what everyone is posting.

I'm in about the same position as wesleyclark, which is i'm about to mod my first card (4850)!!! And i have a few questions. First jason4207, how can you put the middle pin of the blue vr into the fan connector since it isn't in the same line with the other two, and second do i have to use these very small cables (which i don't know how they called and where to find them) you used in your mod or i could use the cables that the fan connector had?

Is the yellow spot that wesleyclark posted right? cause i have read that the right spot is this one
or maybe both can be used?

I would like to thank everyone for the help and the info you provide us.

All 3 pins on the VR's I have slide perfectly into a 3-pin fan connector. I'm not sure what you mean about them not lining up.

I have found that if you don't use smaller cables your mods are much more likely to pop off, and you are going to have heat the components more b/c the thicker gauge wire will wick heat away quickly. I use 30awg wire for the VR's, and 18-22awg for the read points. I hand crimp, and solder all my connections.

I am also curious. That would make my VGPU mod much much easier..

Edit. Also, I am curious. What is the max Voltage I shoudl apply for the memory. I am at 2.07 right now at 1100mhz using the stock cooler. Thanks.

I've heard anywhere from 2.1-2.2 is a safe max, but I wouldn't consider pushing it until you can get aftermarket cooling. The stock HSF puts a lot of additional heat on the RAM chips from the GPU.

Hi, 1st post getting Asus 4850 in a mail tomorrow, planing to put Maze 4 on it and OC it to 800.

Quick question, what voltage do you need for 4850 GPU to reach stable 800MHz. Also is it possible to reach 800 MHz trough BIOS only or Vmod is needed.

Thanks.

Not sure exactly what voltage you'll need, but I think BIOS editing will only get you to 720-750MHz.

who has done the pencil mod? how safe is it? just a regular # 2?

is there a way to check voltage in windows? i dont have a multimeter lol

You need a DMM to even consider doing this. They are a lot cheaper than a new gfx card.

[wesleyclark]

OK. My original image in post #231 has been updated HERE.

The reason i used the pin i did in the first version of my image is because in one of Jimmyz's posts, he said to use the pin next to 601. HERE.

Is that not correct?

[jason4207]

OK. My original image in post #231 has been updated HERE.

The reason i used the pin i did in the first version of my image is because in one of Jimmyz's posts, he said to use the pin next to 601. HERE.

Is that not correct?

Those 2 points might be tied together via sub-layer traces. Check the resistance b/n the 2 points in question. It should read very low 0-0.3Ohms.

As long as you're reading ~5k from the proposed mod point to ground then you're probably in the right spot.

[Miwo]

is there any sort of mod that we can do to increase available Power draw on the 4850???

The 4850 supports a max draw of 150W, 75w on the 6pin, and 75w on the PEG.
The 4870 supports a max draw of 225W, 150w on the double 6pins, and 75w on the PEG......

If ATI puts two connectors on @ 750MHz core + DDR5, that is telling you something right there already. We are running 900~MHz on a single connector

[Theta]

I think you have the wrong spot.

Actually, it's where I've used as well. Easier to get to without the possibility of contacting anything.

Same as the other spots, connected by an inside trace.

[wesleyclark]

So i just got back from radioshack. Only to find out that my Multimeter needs a batter which i don't have, and to find that the soldering iron i got doesn't get hot enough to melt the solder on the boards. AND to find that my solder fell out of a hole in the bag when i was walking home... this is a great day. Ill be going back later tonight and pick up some more solder and get a different iron.
What wattage would you recommend for a soldering iron for this kind of work? I bought a 15 watt, and it isn't powerful enough.

[Theta]

So i just got back from radioshack. Only to find out that my Multimeter needs a batter which i don't have, and to find that the soldering iron i got doesn't get hot enough to melt the solder on the boards. AND to find that my solder fell out of a hole in the bag when i was walking home... this is a great day. Ill be going back later tonight and pick up some more solder and get a different iron.
What wattage would you recommend for a soldering iron for this kind of work? I bought a 15 watt, and it isn't powerful enough.

15W is plenty if you know what you're doing.

If you're referring to melting the main solder posts on the card, you simply need to re-tin the area with fresh solder, and then it will work out perfectly.

For all the SMT and small spots on the board, 15W is more than enough...

[Theta]

For anyone interested, I've played around for the last day or so with a lot of different levels of resistance. I had asked a little while back if anyone had any fixed resistor values, and nobody did.

If anyone is interested in fixed values (assuming 1.046v IDLE / 1.084v LOAD in BIOS), here you go:

vMEM: 100k (5&#37 Fixed Resistor = 2.1v ~ 2.12v

vGPU Idle: 27k (5%) Fixed Resistor = 1.17v ~ 1.20v

vGPU Load: 27k (5%) Fixed Resistor = 1.30v ~ 1.33v

I played around with VRs, but just wanted something solid for this round of testing. Hope this helps somebody out there...

[darkskypoet]

@wesleyclark: Yeah I got a smallish DMM and it needed a sort of strange 12v battery... I think I may even have a soldering iron around here. Probably better that you don't have a huge amount of power for that soldering iron, less easy to melt something horribly necessary. (Like the original solder points).

[wesleyclark]

@wesleyclark: Yeah I got a smallish DMM and it needed a sort of strange 12v battery... I think I may even have a soldering iron around here. Probably better that you don't have a huge amount of power for that soldering iron, less easy to melt something horribly necessary. (Like the original solder points).

yeah, i found pretty much the cheapest DMM i could find at radioshack. Its a shame they wont just put a AA on it or something and be nice to us. As for the iron, the reason i got the 15, was so that i wouldn't melt things. I didn't think to try using a little new solder to melt the old. Ill try that once i replace my lost solder tonight.