ATI 3850/3870 Voltmod thread

Hi, anyone knows how to mod Gainwards 3870 DDR3?
Got an IC called BS-9K near VGA Connector.
Can`t find a datasheet ;(
Here`s a picture.
http://www.ewetel.net/~bernd.hille/gainward.jpg

exciter, can You do some better (more lightened) pictures from that IC and also from bigger area?
It's not hard to find right pin, but due my bad English, I probably can't describe, how to look it.

CRIO - H.O.T. (Hellas O/C Team)

Voltmods at core and mem done

Core worked maximum at 1175mhz
Mem worked maximum at 1150mhz

HD3850 256mb


Aquamark
http://hwbot.org/result.do?resultId=809823
http://hwbot.org/signature.img?iid=181988&thumb=false

3dmark01
http://hwbot.org/result.do?resultId=809820
http://hwbot.org/signature.img?iid=181985&thumb=false

3mark03
http://hwbot.org/result.do?resultId=809821
http://hwbot.org/signature.img?iid=181986&thumb=false

3dmark05
http://hwbot.org/result.do?resultId=809822
http://hwbot.org/signature.img?iid=181987&thumb=false

3dmark06
http://hwbot.org/result.do?resultId=809537
http://hwbot.org/signature.img?iid=181733&thumb=false

Sure, my english is also bad ;)
Wait...

So, i uploaded some pictures here:

PICTURES

Hard to get got ones, because its installed at this time...
Also found the vgpu measure-point i think. it reads 1.337v on the right side to the vga connector.

What's written on that IC I marked on Your pic: http://ceemic.pri.ee/hardware/gainward_3870.JPG ?

It´s marked with:

RT 8105
GSABC0D

Think it`s for memory?!

Yes, RT8105 is for mem.

I think the BS-9K is the vgpu controller, but you to figure out, which pin is the feedback?
I need a datasheet...

It can be found without datasheet also, but it needs lot of measuring. I found FB for Asus HD4850: http://ceemic.pri.ee/hardware/hd4850_2/hd4850_02g.JPG
Do a better macro-pic from that specific area and start to mark all traces from every pin. Use You DMM - set it to lowest resistance measuring mode; it has to show 0,00ohm between connected spots. Then mark ALL GND spots around that IC and ALL spots that are connected to Vgpu (that You previously found near PCIe connector).

FB is connected to GND through a resistor and to Vgpu through another resistor ;)

Okay, will do this tomorrow i think.
Maybe i find this voltage divider...

Hi there,

@Renegade Yes is unmoddet.
Wich volltage did you have at the green marked points http://rapidshare.com/files/181931172/IMG_8213point.jpg
the Same question for Exiter :)

@Exiter i have the Gainward 3850 512MB GDDR3 but locks the same pcb at yours. I need a Voltmod too :)
On wich point(s) you read the Volts on the gpu? Can you marked it, please?
How many MHZ get your card?

@Ceemic can you help me too? Here is the Link again for the pic from the backside of my card http://rapidshare.com/files/181711266/IMG_8213.JPG (full size 10Mpixel)

Sorry my english is horrible, but i hope you understand me enough.

Regards


Edit: Here is my Bios file (original) http://rapidshare.com/files/18192804...Org__RV670.bin

So i just measured some traces and found this one marked on the picture.
Between the GND & VGPU Spot is a 1500µf / 6,3V Cap so i measure 3,1Ohm between these spots.
Resistance between each GND & VGPU Spots are 0,6Ohm, because of measure wire...
So what do you think?!
In Circuit measurement from both resistors: 3,2kOhm.

regards,

steffen

http://www.ewetel.net/~bernd.hille/3870HD.JPG

In theory, this can be right, but You have to trace all the pins. There can be more than 1 "possible" FB pin, but only one is the "right".

If Your soldering skills are good, then solder 50kohm VR between one spot on that trace and GND. If it is FB pin, then Vgpu should change a little. Then turn the VR so the resistance starts to drop. If Vgpu doesn't change at all, then don't turn resistance too low! Just unsolder the VR and start looking another pins.
There are risks involved, but if You know what You are doing, then You should find FB soon!
Good luck!

I soldered it an hour ago.
Only had 200kOhm Trimmer, but all is working like it should.
Got good solder skills, so it was no problem for me, but i think its better to go with pencil-mod...

Nice to hear it's working :)
But why pencil mod? :rolleyes:

i mean for someone without soldering skills its safer to do the pencil mod, since the resistors are 1,x mm small or so.
http://www.ewetel.net/~bernd.hille/100_2453.JPG

So, which resistor to pencil in?
I want to pencil mod, to make sure there is nothing wrong with the card itself (limiting me to 760 core, even after I re-hashed the bios)
To see if the Core will OC better with a little extra voltage...
My mobo is fully V-modded, as was the mem on my HD3650. (DMM & soldering iron use at school ftw)

Hi Renegade,
I do the mod with exiter together. For Pencil mod take the pic in post 938 and the blue marked resistor.
My stock Voltage is 1,27 at 2,353Ohm at 2,220Ohm the Voltage on Gpu is 1,38 in 3D 1,40V.

With stock Voltage the ATI Tool shows artefacte at 823 Core with Mod at 891Core. Benching without Mod goes to 850 Core but with mod only 877 at the Moment.
My system runs not stable but i don´t no why? With 904 on Core i didn´t see any artefact´s but my TFT goes off after 2minutes in Bench. The same at 891 and 877 and 864 but 850 runs.
Sometime the Benchmark runs with 877 goog other time the TFT goes of.

An how to is following

Another question,

with core running @780Mhz i get 1,326V idle and 1,405V with artifact scanning (ati-tool)? Why its increasing the voltage???
With mod, pot @highest value 200kOhm i get: idle 1,343V, artifact-scanning 1,418V.
Seems to be something with Bios-Values???

Gainward 3850 / 3870 seems to be protected against high current /voltage.
DoDo and me getting an Blackscreen while benching with 1,4xV and higher Clocks.
VGPU drops to almost 0,0V...Maybe a newer Bios will help? Or only harmodding??

Same issue here, It's like the bios is locked or something.
Im not sure.
I'm going to try flashing to another bios. I'll let you know if this helps.
I get blackscreen at 775mhz core on stock volts, yet, 760 passes every time, which makes me think that the bios is locked.

Hmm...thats funny.
Whats your vgpu controller called?
BS-??

Renegade i didn´t think the Bios ist locked.
I think it´s a other Problem.

Bench with Core 920/1100 and CPU runs at 2,4Ghz all OK
Bench with gfx-card at stock and CPU at 3,8Ghz all OK
Bench with gfx-card at 920 and cpu at 3,8Ghz = Blackscreen
Bench with 850 and 3,8Ghz all OK
Bench with 864 / 3,8Ghz Blackscreen
Other times he run with 877 / 3,8Ghz LOL

Verry confused this.
Wich Bios did you have Renegade? Maybe you can use mine at Post 937 if you have the 512MB version.

I just swapped over to the Qimonda ASUS bios.
Running at 780/1035 without any kind of blackscreen.
Any higher promotes bad behaviour.

I will do the pencilmod tomorrow.