ATI 3850/3870 Voltmod thread

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12-04-2007, 04:23 PM
ryanmartini

Quote:

Originally Posted by STEvil

To keep from shorting the GPU voltmod you guys might also want to look at putting a fixed resistor in series with the VR... I would say a 10K fixed should do for most but it might be a bit high for getting 1.6v+...

Ok so with the VR soldered to the two points, where would the resistor fix into place?

Also, someone take some pics of the mod, dont be greedy! :D
12-04-2007, 04:25 PM
K404

See my pics on the previous page.

The resistor would be in series with one leg of the pot.

ie: solder point-> resistor-> leg of pot
12-05-2007, 10:56 AM
Unoid

Can someone share with us what Values of resistance equate to vgpu values?

I like toe hard wire w/o a POT. strait resistors ;-) But I'd like to use a smaller POT also. Everyone says 100kohm, but what do you end up at to achieve 1.5vgpu? 15k? 50k? if so I'll buy a 50kohm.
I haven't hard modded since my 9600Pro. Will be fun to volt and watercool again.

1kgpu on water and 1.5-1.6vgpu sounds like fun.
12-05-2007, 01:28 PM
JamesBong420

3850 is here... give me a few days to mess with her then hardmod here we come!!!!!!!!!!! and chiller !!! ! !!:yepp: :yepp: :cool: :rolleyes: :D
12-05-2007, 03:32 PM
winbond

can someone post some real benchmarks of the overclocked 3870?

like crysis 1280x1024 with EVERYTHING maxed out, etc,

thanks
12-05-2007, 04:49 PM
Sage

i can tell you that i run crysis at 1650x1080 with High Everything with a couple of settings Very High.

Though not really any use cause games arnt just dependent on ur gfx card. See my specs below.
12-05-2007, 08:02 PM
JamesBong420

hardmod confirmed to work on the 3850. the stock 3850 volts are 1.22v 100k VR got it to 1.28 im at 1.3 816mhz core and still testing... :D :D :D
12-05-2007, 08:17 PM
slugzkea

I volunteer!

I believe my specs below are the most generic for today's setups and my comp should do the crysis bench.

All i need is a photographic diagram of the completed mod and I can get the mod done in less than 30 mins.

I know for sure that 1650x1050 crysis everything high at 877/2600 i get a good 20-30fps or lower.
12-05-2007, 08:41 PM
JamesBong420

x2 3800 @ 3.0
Crucial Ballistix ddr500
msi 3850 823mhz/945mhz

9733 3d06- http://service.futuremark.com/compare?3dm06=4047261

im happy so far... 10k is my goal..:yepp: :yepp:

edit: 3d06 9889
850/999 1.44v http://service.futuremark.com/compare?3dm06=4047847
12-06-2007, 04:42 AM
R*r

ive done the mod but i dont know why every time i set the core clock above 860 it will hang?ive set the vgpu at 1,5 1,4 doesent make any difference?

and if i set the core clock directly at 900 or above the core clock reading show me 34Mhz at riva tuner??very strange???

any one can help?
12-06-2007, 05:01 AM
the-strokes

Quote:

Originally Posted by R*r

ive done the mod but i dont know why every time i set the core clock above 860 it will hang?ive set the vgpu at 1,5 1,4 doesent make any difference?

and if i set the core clock directly at 900 or above the core clock reading show me 34Mhz at riva tuner??very strange???

any one can help?

try the modified bios.
12-06-2007, 05:40 AM
R*r

thanks man,now im benching @ 1G :up:
12-06-2007, 07:56 AM
JamesBong420

i wish the bios fixed the 3850s 860 mhz lock.... :shakes: :shakes: :shakes:
12-06-2007, 11:39 AM
os008

Guys, what's a good up-to-date utility to edit an ATi BIOS file?

RadEdit, and RaBiT are way too old right now, will NiBiToR work, or is it only for nVidia BIOS'.

Thanks.
12-06-2007, 04:29 PM
Amrita

thank's guys worked like a charm but i had to go 1,5 for a stable 945mhz
next step is to reseat my wb but i'm waiting til i'm adding a new card hafto rebuild my loop then anyway

any fix to get crosfire oc higer yet?
12-06-2007, 07:14 PM
SNiiPE_DoGG

http://www.radioshack.com/product/in...entPage=family

what do you guys think of this potentiometer for the voltmod on the 3870?
12-06-2007, 08:43 PM
c.freak

Has thee been any confirmed ideal voltage for the VDDR mod? and What VR-size/resistance should this POT have?
I haven't done hardmod since the 9800 and X800 time, so it's been a while :D
For the moment im only doing 900mhz on the core. Boring stockcooler soon goes off.

For the cooling later on i'll be using a triple-radiator + 6x 120 fans for my new MCW60's. Cpu,Nb+Sb will go off with the same cooling. For the moment not really finished with my project. So cooling shouldn't be any problem.
12-07-2007, 12:19 AM
largon

Quote:

Originally Posted by SNiiPE_DoGG

http://www.radioshack.com/product/in...entPage=family

what do you guys think of this potentiometer for the voltmod on the 3870?

It would work but personally, I'd use a multiturn VR.
Single turn pots like that are very inaccurate for vmodding.
12-07-2007, 12:40 PM
SNiiPE_DoGG

Quote:

Originally Posted by largon

It would work but personally, I'd use a multiturn VR.
Single turn pots like that are very inaccurate for vmodding.

ty very much, im off to radio shack!
12-07-2007, 06:02 PM
JamesBong420

finally broke 10k with my x2 3800 - 3850 850mhz/999mhz yahooooooo :D

http://service.futuremark.com/compare?3dm06=4075418
12-08-2007, 05:53 AM
MorGo7h

Quote:

Originally Posted by JamesBong420

finally broke 10k with my x2 3800 - 3850 850mhz/999mhz yahooooooo :D

http://service.futuremark.com/compare?3dm06=4075418

Gratz :up:
12-08-2007, 05:57 AM
quake6

Quote:

Originally Posted by JamesBong420

finally broke 10k with my x2 3800 - 3850 850mhz/999mhz yahooooooo :D

http://service.futuremark.com/compare?3dm06=4075418

Now go for 11k :D:up:
12-08-2007, 09:59 AM
MorGo7h

Any differences between HD3870 and Vmodded? Since the Vmodded bioses dont work :/

Nvm: I saw some results on page 3 WTF! I want a 2nd watercooling loop!! :p
12-08-2007, 11:06 AM
R*r

finally can touch 15k :D
http://service.futuremark.com/compare?3dm06=4087007
12-08-2007, 11:46 AM
SNiiPE_DoGG

http://cgi.ebay.com/ws/eBayISAPI.dll...ksid=p3907.m29

i got one of these pots for my mod, opinions?
12-08-2007, 02:08 PM
afireinside

100k... All I have right now are 50k :( Anyone know how many ohms are needed for ~1.5vgpu?

Any vmem mod found yet?
12-08-2007, 02:17 PM
K404

dude...VMem mod is DONE the only thing missing is the ideal pot value.

Someone should take the initiative and friggin TRY it.

Start with 100K....tune down until it bites then measure the resistance.

Jeeezzzzzz

AFI...I know you KNOW this!

[/exasperation]
12-08-2007, 02:31 PM
afireinside

Ah sorry didn't check the thread. Just got my cards and I've been busy trying to get them to work in games. I'd try if I had 100k VRs but I don't.

And no, I don't know anything about volt mods.
12-08-2007, 02:37 PM
purecain

send your cards back if they dont work in any games, or elaborate...
12-08-2007, 02:57 PM
afireinside

Quote:

Originally Posted by purecain

send your cards back if they dont work in any games, or elaborate...

They work... Just not well. Ut3 drops to 30s a lot and CF won't work in hellgate london or crysis.
12-08-2007, 03:18 PM
largon

What is the resistance between vMEM solder points?
Around 4kΩ?
12-08-2007, 03:20 PM
purecain

crossfire does work in crysis on mine, must be a driver issue with your rez and hellgate london works fine for me aswell in crossfire... looks like your having some bad look.
try returning your cards as something is wrong at your end...
are you on vista and have you installed the multigpu hotfix????
12-08-2007, 04:00 PM
afireinside

Quote:

Originally Posted by purecain

crossfire does work in crysis on mine, must be a driver issue with your rez and hellgate london works fine for me aswell in crossfire... looks like your having some bad look.
try returning your cards as something is wrong at your end...
are you on vista and have you installed the multigpu hotfix????

MultiGPU hotfix... That might be a good idea :ROTF: :rofl:
12-08-2007, 04:08 PM
JamesBong420

Quote:

Originally Posted by oanvoanc

hi k404

here the picture of the whole card.

http://img101.imageshack.us/img101/7069/img0283af0.jpg

here you go at least for the vcore. :cool:

http://buydurango.com/josh_files/vcore.jpg
12-09-2007, 01:53 AM
Klimpen

Hi all, I see a few that want a picture taken AFTER the vGPU mod has been done.
I can provide that because I understand what to do, I have a 3870, I have very good experience with soldering small
components (even SM-components) and of course I have a camera and a webhost..
The only thing I'm missing is a VR of 100kOhm. It's sunday here and EVERY store is closed.
I will ask my friend at work tomorrow for a 100kOhm VR.

Even though I have stock cooling on right now I have a EK waterblock on order so that should be settled in a couple of days.

When I'm done with the mod I will try to take several pictures and help out as much as possible.
Ohh, I have one question though, when I'm done with the mod and everything is ready to go!
How do I know where to start with the VR.
Is it just a matter of trial and error? To start with it set to max resistance (100kOhm) and then
slowly turn it "down" and measure the vGPU readout until I get what I want (about 1.5v)?
I have actually pretty good knowledge in soldering and electronics but have never done a vMOD of this kind before :slapass:

##EDIT##
I have to chose from one of the following ones, any opinions?

http://www.elfa.se/images/lowres/l5560.jpg
type 44 Y for SM with only 10 turns

http://www.elfa.se/images/lowres/l5561.jpg
type 64 with 15 turns

http://www.elfa.se/images/lowres/l5605.jpg
Type 67W with 20 turns

http://www.elfa.se/images/lowres/l5596.jpg
Type 89P with 20 turns
12-09-2007, 03:37 AM
Amrita

i went with the 15 turn's one was acurate enough actualy perfect
a 20 i think u will hate, to mouch hassle turning hehe

as for finding the right resistance u got it right set it too max resistance then solder it on and boot up
messure the volt and start turning a round at a time and messure untill u get a new readout then turn with care untill u hit the sweet spot^^
12-09-2007, 09:49 AM
Mayk-Freak

2 x 3870 Volt-Mod

http://www.abload.de/img/modigst.jpg
12-09-2007, 11:39 AM
JamesBong420

now thats what i call CLEAN!!!! :cool: :p: :D
12-09-2007, 02:02 PM
jimmyz

somebody beat me I see lol. I am still limited to 864 by bios but stilt said soon the 3850 bios will be out. what's worse is i can't get any utility to clock the second card past 770 core.
[IMG]http://img223.imageshack.us/img223/4...tmod007rk4.jpg[/IMG]
12-09-2007, 05:11 PM
Mayk-Freak

C2D@4180MHz -4GB Crucial- 2xHIS HD3870@1012/1341MHz

Vista 64Bit

http://www.abload.de/img/neueergebniosse0fd.jpg
12-10-2007, 12:21 AM
Unoid

Nice clocks with dual voltmodded 70's.
12-10-2007, 11:19 AM
pepinorang

Quote:

Originally Posted by K404

dude...VMem mod is DONE the only thing missing is the ideal pot value.

Someone should take the initiative and friggin TRY it.

Start with 100K....tune down until it bites then measure the resistance.

Jeeezzzzzz

AFI...I know you KNOW this!

[/exasperation]

I'm on HD3870 (one card 930/1340 and the other 902/1340 ALL stock) I'm just awaiting EK waterblocks and trimmers to do both mods don't worry about it I'm adventurous so I take the initiative ;) will give my feedback here next week I think :up:

Bye
p€p|n0r@ng
12-10-2007, 12:27 PM
kemist

Quote:

Originally Posted by pepinorang

I'm on HD3870 (one card 930/1340 and the other 902/1340 ALL stock) I'm just awaiting EK waterblocks and trimmers to do both mods don't worry about it I'm adventurous so I take the initiative ;) will give my feedback here next week I think :up:

Bye
p€p|n0r@ng

What are you using to clock the cores? Atitool doesnt work, rivatuner works, but only for one core (for me at least), and ati tray tools didnt appear to work.

Ahh ok, was using ati tool .27 B3, will give it a try when i get home, thanks.
12-10-2007, 12:47 PM
JamesBong420

atitool .27 b4 works for me. 3850

http://www.techpowerup.com/wizzard/ATITool_0.27b4.exe
12-10-2007, 04:55 PM
pepinorang

Quote:

Originally Posted by kemist

What are you using to clock the cores? Atitool doesnt work, rivatuner works, but only for one core (for me at least), and ati tray tools didnt appear to work.

Ahh ok, was using ati tool .27 B3, will give it a try when i get home, thanks.

Rivatuner works properly for me but there is a "procedure" to follow if you want to clock CF ;) but for me now it's bios-modded :D
12-11-2007, 11:41 AM
kemist

1 Attachment(s)

Quick question.

Would it be bad if i were to bridge these two points with solder? It looks like the are connected by the pcb and so it wouldnt matter if the were bridged?
12-11-2007, 12:32 PM
oanvoanc

thanks for your help k404.

here my mod (i didnt use it yet because i already maxed the card out under ln2 without "activating" the mod -> 857mhz)

http://img45.imageshack.us/img45/3167/dsc00631oo7.jpg

this is a result under liquid nitrogen - without any voltmod.
so you dont need this mod under cold unless the vco clock divider problem has been solved:

http://img107.imageshack.us/img107/4...3850857ja3.jpg

okok - big surprise - big surprise! :D

today i tested the card just with watercooling - still without activated voltmod.
i kept the temperature below 21 degree celsius (load) and had a stable 857mhz core frequency..... very interesting :rolleyes:
12-11-2007, 09:31 PM
Unoid

why interesting? use the bios that fixes the probelm and 1ghz should be your goal!
12-12-2007, 04:20 AM
oanvoanc

i dont think this would work.
i heard that this bios would just work for the hd 3870.
12-12-2007, 08:11 AM
largon

Quote:

Originally Posted by kemist

Quick question.

Would it be bad if i were to bridge these two points with solder? It looks like the are connected by the pcb and so it wouldnt matter if the were bridged?

You can do that.
These points are connected via PCB trace already.
12-13-2007, 09:53 AM
chp

Quote:

Originally Posted by JamesBong420

atitool .27 b4 works for me. 3850

http://www.techpowerup.com/wizzard/ATITool_0.27b4.exe

It Works??? :confused:

Everytime I try to apply the new values (0.27b3 or 0.27b4) the system crashes. :shrug: I have a Connect3D 3850 512MB.

It work only if I use it in conjunction with RT 206, not alone.

Else, Someone has the resulting values from the 100K VR?
12-13-2007, 10:30 AM
JamesBong420

yup it works for me. make sure you have "if card has 2d 3d clocks,switch to 3d..." is checked and suspend while ATItool is running resume on quit. in the HD 2000 overclocking section. which is in settings. i know dont make any sense but i hope that helps..:rofl:
12-13-2007, 03:45 PM
chp

Unfortunately it doesn't. :mad:

Could it be a conflict with CCC?
Perhaps I missed something?
12-13-2007, 08:52 PM
Sage

bring on the VMEM damnit! i gotta see 1400Mhz at least! :D
12-15-2007, 03:56 PM
afireinside

So does anyone know what the VGPU would start at if I were to use a 50k VR?
12-15-2007, 04:01 PM
jimmyz

Quote:

Originally Posted by afireinside

So does anyone know what the VGPU would start at if I were to use a 50k VR?

about 1.42
use two and set them both too the max.
12-15-2007, 04:07 PM
oanvoanc

i dont know at which voltage it would start.

but i tested both:

2x50k ohm and 1x100k ohm set to the max.
both result in 1,08v 2d and 1,24v 3d.

(measured on two power color hd 3850 ;)
12-15-2007, 07:40 PM
afireinside

Quote:

Originally Posted by jimmyz

about 1.42
use two and set them both too the max.

Thanks. I'd use 2 but I only have 2 of them on hand and I have 2 3870s ;)
12-16-2007, 01:16 AM
gurusan

I have a Powercolor 3850 512mb and my PCB looks different than those I see pictured in this thread. However, I shaded the circled resistor and managed to get my core to 1012mhz stable :D Temps don't go over 47c load but I am on water.

The thing is, I don't know what voltage I am running...Can anyone tell me where to measure my vGPU?

http://img84.imageshack.us/img84/9079/img2953jk5.jpg
12-16-2007, 05:35 AM
largon

gurusan,
There are several vGPU measuring points in the pic you posted.
All those metallic spots on the bright red area on the far right side of your pic are vGPU measuring points.
12-16-2007, 06:13 AM
os008

So, i got the courage yesterday to do the volt-mod, and i did, and after much testing, i reached a stable 859/999 at 1.4v, max temp of 75c at a 60% fan duty.

Had a lot of trouble getting a cool idle temp with RivaTuner, or even ATI Tool, so i just editted the BIOS of the card to clock itself to 859 on load, and it worked ... no more manual overclock and above all 35c idle temp :).

Just waiting now for Stilt's BIOS, wonder why he's taking so long to post it 0.o
12-16-2007, 07:17 AM
gurusan

Quote:

Originally Posted by largon

gurusan,
There are several vGPU measuring points in the pic you posted.
All those metallic spots on the bright red area on the far right side of your pic are vGPU measuring points.

Which ones in particular? I've tried all them but they give bogus readings like .8 and 1v

Quote:

Originally Posted by os008

So, i got the courage yesterday to do the volt-mod, and i did, and after much testing, i reached a stable 859/999 at 1.4v, max temp of 75c at a 60% fan duty.

Had a lot of trouble getting a cool idle temp with RivaTuner, or even ATI Tool, so i just editted the BIOS of the card to clock itself to 859 on load, and it worked ... no more manual overclock and above all 35c idle temp :).

Just waiting now for Stilt's BIOS, wonder why he's taking so long to post it 0.o

Congrats!!

On a side note...I just did a 3dmark06 run and got 14,815 :D

http://service.futuremark.com/compare?3dm06=4210636
12-16-2007, 08:08 AM
HousERaT

any pencil mods for the 3870?
12-16-2007, 08:15 AM
gurusan

Quote:

Originally Posted by HousERaT

any pencil mods for the 3870?

Is it not the same as the 3850?
12-16-2007, 09:03 AM
os008

Quote:

Originally Posted by gurusan

On a side note...I just did a 3dmark06 run and got 14,815 :D

http://service.futuremark.com/compare?3dm06=4210636

You can run at 1GHz? how? can you share your BIOS with us please?

EDIT: OH, nevermind, thought you had 256MB version, just saw your sig again.

Thanks.
12-16-2007, 10:03 AM
gurusan

Well I was being stupid before and those metal points certainly are vGPU measure points.

I was at 1.84v :p I have no problem pushing limits but even that is a bit roasty for me on a 55nm process, watercooling or not. So I've lowered clocks to 840mhz.... 1.4v idle 1.5v load ....now temps are 29c idle 37c max load

Would like to figure out a gddr3 vdimm mod for this card, and once I've pushed the limits I will need a new toy :p

http://img135.imageshack.us/img135/4...emptempzh8.jpg
12-17-2007, 10:35 AM
os008

What's the max safest voltage for 3850 please? or in general, what's the max voltage in % that most usually don't pass?
12-17-2007, 11:43 AM
LowRun

Quote:

Originally Posted by gurusan

Well I was being stupid before and those metal points certainly are vGPU measure points.

I was at 1.84v :p I have no problem pushing limits but even that is a bit roasty for me on a 55nm process, watercooling or not. So I've lowered clocks to 840mhz.... 1.4v idle 1.5v load ....now temps are 29c idle 37c max load

Would like to figure out a gddr3 vdimm mod for this card, and once I've pushed the limits I will need a new toy :p

:eek: :shocked: Now that is some serious volts :yepp:
12-17-2007, 12:40 PM
RealyPssd

Is there any updates/word on when ATI Tool will be updated with s/w voltage control for the HD3xxx's yet?
12-17-2007, 02:39 PM
MsB

Wow thats great gurusan I have two of those cards and I'm waiting for good overclocking tool for cf. I will try the pencil mod when one comes out. what water block are you using?
12-17-2007, 03:28 PM
LowRun

Quote:

Originally Posted by RealyPssd

Is there any updates/word on when ATI Tool will be updated with s/w voltage control for the HD3xxx's yet?

No other timeframe than "soon" was given but w1zzard also said that voltage control would be very limited unfortunately :(
12-17-2007, 03:51 PM
RealyPssd

Does anyone know if you can adjust HD3xxx voltages with that new Phenom/790 Overdrive application since it is part of that spider platform?
12-18-2007, 06:48 AM
kemist

Quick question, would this trimmer work for this mod?

Technical/Catalog Information 490-3009-ND
Standard Package 50
Category Potentiometers, Variable Resistors
Family Trimmers
Vendor Murata Electronics North America
Resistance In Ohms 100K

Power (Watts) 0.25W, 1/4W

Number of Turns 12

Package / Case Through Hole

Packaging Bulk

Adjustment Type Top Adjustment

Tolerance ±10%

Series PV37

Lead Free Status Lead free
RoHS Status RoHS compliant
Other Names 490-3009
490-3009-ND
PV37Y104C01B00
12-18-2007, 10:41 AM
Norway

http://img129.imageshack.us/img129/2...inalql8ux0.jpg

Havent testet it becuase 1350Mhz is more then enough for me ;)
12-18-2007, 10:51 AM
Norway

I have now pencil mod'd the vcore so the circuit is a total off 4.59Kohm, default is it 5.1Kohm

Hope some good results ;)
12-18-2007, 11:31 AM
Sagart

Quote:

Originally Posted by Norway

I have now pencil mod'd the vcore so the circuit is a total off 4.59Kohm, default is it 5.1Kohm, what voltage should i expect vcore to be ?

I can calculate it if someone can give me a ohm value at a certain voltage

What's the stock voltage? :)
12-18-2007, 11:37 AM
HousERaT

Quote:

Originally Posted by Norway

I have now pencil mod'd the vcore so the circuit is a total off 4.59Kohm, default is it 5.1Kohm, what voltage should i expect vcore to be ?

I can calculate it if someone can give me a ohm value at a certain voltage

Are you pencil modding a 3870? Where is the place that you used the pencil? Is it the same place as in post #159?
12-18-2007, 12:02 PM
Norway

It is 1.33v but on my card it is 1.36v stock ......
12-18-2007, 12:09 PM
Norway

I penciled the blue line
http://img409.imageshack.us/img409/2...odsmallke9.jpg

Or any other green spot to GND should work if i'm not completely screwed atm
12-18-2007, 12:11 PM
gurusan

Quote:

Originally Posted by MsB

Wow thats great gurusan I have two of those cards and I'm waiting for good overclocking tool for cf. I will try the pencil mod when one comes out. what water block are you using?

MCW60 :)
12-18-2007, 12:23 PM
HousERaT

Quote:

Originally Posted by Norway

I penciled the blue line
http://img409.imageshack.us/img409/2...odsmallke9.jpg

Or any other green spot to GND should work if i'm not completely screwed atm

Simple enough....... now lets some some before and after results. :)
12-18-2007, 12:29 PM
Norway

Be patient my young padawan
12-18-2007, 12:29 PM
HousERaT

Quote:

Originally Posted by Norway

Be patient my young padawan

I'm waiting like a trick on a street corner. :D
12-18-2007, 01:31 PM
Norway

strange, at 4.6Kohm I got stock volt, on 2.28Kohm i got the same result :(
12-18-2007, 02:10 PM
roger_h99.nor

:eek:
Consider yourself lucky. If, be chance, you've got the right spot to shade, you would have killed your card with that voltage.

Recommend some readup on the basics on v-modding.
12-19-2007, 04:22 AM
gurusan

Is there a vdimm mod for the 3850?
12-19-2007, 06:28 AM
Norway

Quote:

Originally Posted by roger_h99.nor

:eek:
Consider yourself lucky. If, be chance, you've got the right spot to shade, you would have killed your card with that voltage.

Recommend some readup on the basics on v-modding.

Well 4.6Kohm should give me around 1.5v, but it didnt happend so i tried half of it, also tried to shade the resistor but nope :(

Now i have taken som 470Kohm VR from school, but i am only to run stock air for now, water later so i wait for the solder work ;)

TIP: Run your card on 50% fan 24/7, my max temp is 65C load on stock volt on 3870 ;)
12-20-2007, 07:21 AM
KainXS

I just found out something unexpected, one of my 3850's has ram rated at DDR3 1000 and the other has it rated at 900, ATI could have easily overclocked these cards to have 1100 because the 8800GTS XXX uses slower DDR3 800 and can reach 1265, at least on my old one I could.

the voltage on both is 1.8V

Powercolor 3850 XTREME
Powercolor 3850 256
12-21-2007, 05:54 AM
Niccolò

Quote:

Originally Posted by Norway

Well 4.6Kohm should give me around 1.5v, but it didnt happend so i tried half of it, also tried to shade the resistor but nope :(

Now i have taken som 470Kohm VR from school, but i am only to run stock air for now, water later so i wait for the solder work ;)

TIP: Run your card on 50% fan 24/7, my max temp is 65C load on stock volt on 3870 ;)

Because that's the wrong spot.

I think i'm figuring it out, just wait a little bit and i'll post the resistor to shade.
12-21-2007, 09:33 AM
Niccolò

Here it is

http://img249.imageshack.us/img249/6679/dscn2700xp3.jpg

I had 0.1v increment by reducing it to 1.3 KOhm, so you can count if you want ;)

Ps: obviously there's a K missing between 2.26 and Ohm :up:
12-21-2007, 02:17 PM
KainXS

and that will increase voltage?
12-21-2007, 02:28 PM
Clint

Quote:

Originally Posted by Niccolò

Here it is

http://img249.imageshack.us/img249/6679/dscn2700xp3.jpg

I had 0.1v increment by reducing it to 1.3 KOhm, so you can count if you want ;)

Ps: obviously there's a K missing between 2.26 and Ohm :up:

Hmm, my default HIS 3870 has a 1.62kOhm value there..:confused:

I did measure voltage and it is 1.34v, so there is something that doesn't add up.
12-21-2007, 02:49 PM
HousERaT

I'm ready to start testing pencil mods as soon as someone demonstrates a working mod for the 3870......... ;)
12-21-2007, 03:05 PM
RealyPssd

Me too, hot damn.
12-21-2007, 03:38 PM
Niccolò

I have a Sapphire 3850 512mb. For me it worked great... Dunno about your card, just try and you'll know it. But 99% i can bet it's the same mod for all cards (that has this pcb of course) ;)
12-21-2007, 04:18 PM
HousERaT

Quote:

Originally Posted by Niccolò

I have a Sapphire 3850 512mb. For me it worked great... Dunno about your card, just try and you'll know it. But 99% i can bet it's the same mod for all cards (that has this pcb of course) ;)

so voltage went from what to what, and how much did it help your overclock?
12-21-2007, 04:51 PM
Niccolò

I only raised it to 1.3v from 1.2v couse i'm on stock cooling.

Overclock went from 750 to 820.

I also tried a 1.35v an this is the result

http://www.pctunerup.com/up/image.ph...06864-954-.JPG
12-22-2007, 12:10 AM
Clint

I shaded it down to 1.10kOhm from originally at 1.62kOhm.

Changes were:

1.62kOhm: 2D 1.24v and 3D 1.334v (891Mhz ATI Tool)

1.10kOhm: 2D 1.30v and 3D 1.40v (931Mhz ATI Tool)

(1.00kOhm: 2D 1.32v and 3D 1.415v) (945Mhz ATI Tool)

So it's confirmed working:up:

EDIT: after some testing I can conclude that I have gained 40Mhz from raising 0.07 volt, wich I think is pretty darn good under a stock cooler:up:
I now can run furry cube in ATI tool at 931Mhz, instead of 891Mhz.

Temps went up from 52C to 57C with stock cooler at 80%.

All in all a very sweet mod. :clap:
12-22-2007, 01:24 AM
Clint

Finished a first bench in 3D06 @ 945/1250 without any hickups or artefacts.

Max load temp with stock fan at 100% was 54C.

EDIT: 1 hour of Crysis @ 945/1200 no problemo whatsoever, it actually seems like the stuttering and querkiness that I noticed before is gone...the voltage injection surely did wonders.
Max temp in Crysis was 57C, and I think thats the max I wanna do on stock heatsink.

Next step is to slap my modified 7900GTO cooler on there, 4 6mm heatpipes and some home made high flow ducting will allow 1.5 volt and 1Ghz on air...no question about it.:D
12-22-2007, 05:01 AM
Mayk-Freak

my self modded HD3870 babies:
http://www.abload.de/img/modi3al.jpg

C2D@4180MHz & 2HD3870@ 1012MHz/1340MHz 3DMark06 19323 Punkte Vista64Bit

http://www.abload.de/thumb/neueergebniossejj7.jpg

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