GTX285 various mods.. which may work for GTX260/280/295 also

[NapalmV5]

sorry nickless no pencil but all it takes is silver conductive paint to bridge a vid pin

http://www.xtremesystems.org/Forums/...2&postcount=56

if you bridge vid pin 2 and 4.. take a look at post #71 by cryptik

and results @ post #73 by dengyong

[nickless]

sorry nickless no pencil but all it takes is silver conductive paint to bridge a vid pin

http://www.xtremesystems.org/Forums/...2&postcount=56

if you bridge vid pin 2 and 4.. take a look at post #71 by cryptik

and results @ post #73 by dengyong

Thank's mate, you are great. Last question, can I remove this silver conductive paint and how, when I decide to sell the card?

[CryptiK]

Yes silver conductive paint is easily removed with some isopropyl alcohol or acetone on a Q-tip. If you use acetone be careful what you get it on, it is quite a strong solvent, but I have not had an issue with it yet.

[CryptiK]

Napalm, would you mind measuring the shader voltage on your cards? I use one of the small caps a centimeter or so towards the rear of the card from the shader chip (on the back of card) - I'm pretty sure this is the shader voltage anyway.

[dengyong]

For anyone confused about the vmod here's a pic.
All credit to CryptiK and NapalmV5.

[nickless]

I made it, I bridged 2 and 4 pin with silver conductive paint and now I have 1.22v Vcore and 2.12v Vmem. Thank's a lot to NapalmV5, dengyong and CryptiK .
Get some test now

[dengyong]

I made it, I bridged 2 and 4 pin with silver conductive paint and now I have 1.22v Vcore and 2.12v Vmem. Thank's a lot to NapalmV5, dengyong and CryptiK .
Get some test now

NapalmV5 and CryptiK did all the work and deserve all the credit.

[ChinStrap]

hmm, i have an eVGA SSC - the first three from the left already have resistors on them. thats all though, 1,2 and 3 - the rest are blank.

would bridging set 4 help any you think?

[ChinStrap]

actually, looking again - 1,2,3 and 11 are resistored already.

[CryptiK]

1/2/3/11 is normal for SSC version, this gives ~ 1.23vgpu/2.15vmem. If you bridge 4 you will get a little extra voltage. I currently have 1/2/3/4/11 bridged and I'm experimenting with other arrangements.

[ChinStrap]

As Napalm said just bridge it with solder, the 'resistors' they use are 0 - 0.1 ohms anyway (basically a dead short between the 2 contacts). Max stable clocks did improve after the mod.

On my card (base model EVGA):

1/3/11 = 1.16 vgpu / 2.11 vmem
1/2/3/11 = 1.22 vgpu / 2.13-2.14 vmem

EDIT - bridged the 4th contacts (so now have: 1/2/3/4/11 bridged), now have 1.23 vgpu / 2.15 vmem under load, basically at SSC voltages now.

Raising voltage hasnt had a large effect on load temps, before mods on auto fan speed it was ~80*C in really heavy scenes of crysis, at 1.22v is was around 83*C, and now at 1.23v it's around 85*C (but today is warmer weather too). Fan doesn't go over 72%.

hmm. i just saw this. adding the 4th pin does infact give the extra .01 on vcore?

[ChinStrap]

this is a great thread. i thank you guys for your willingness to share!

your efforts are appritiated

[CryptiK]

Yes for me bridging 4 gave me an extra 0.01v on both vgpu & vmem.

[chispy]

Thanks for this guide guys ,well done. I would like to know where to measure v.core and v.mem ? where are the points to check with DMM ? i just got an xfx GTX 285xxx and i would like to measure my stock voltage and try this mod after testing the card on stock volts.
Any help and guidance will be greatly appreciated.

chispy.

[CryptiK]

I made it, I bridged 2 and 4 pin with silver conductive paint and now I have 1.22v Vcore and 2.12v Vmem. Thank's a lot to NapalmV5, dengyong and CryptiK .
Get some test now

I was going to reply to your PM but it looks like you have it sorted now.

Thanks for this guide guys ,well done. I would like to know where to measure v.core and v.mem ? where are the points to check with DMM ? i just got an xfx GTX 285xxx and i would like to measure my stock voltage and try this mod after testing the card on stock volts.
Any help and guidance will be greatly appreciated.

chispy.

Hey Chispy, here's the points I use. Red = vgpu measure point, green = vmem measure point.

[NapalmV5]

^ dengyong/cryptik - thanks

nickless - looks like you got it figured out thanks to cryptik/dengyong

if you guys also bridge vid 10 you may get 1.24-25vcore

if you guys want ~1.26vcore which is the most doable right now/~2.17vmem.. just solder a 22k resistor from ground to one of the points @ vid 2

your welcome guys

NapalmV5 and CryptiK did all the work and deserve all the credit.

forget credit.. sharing is more rewarding

[NapalmV5]

Napalm, would you mind measuring the shader voltage on your cards? I use one of the small caps a centimeter or so towards the rear of the card from the shader chip (on the back of card) - I'm pretty sure this is the shader voltage anyway.

is it the smaller cap above/right of C1285 ?

[CryptiK]

I measured 1.18v at both caps to the right of where 'C1277' is written on the PCB. I may be wrong though this might not be shader voltage.

Also I just bridged VID 10 (as well as having 1/2/3/4/11 bridged) and got no change in voltage. Then I removed VID 4 leaving 1/2/3/10/11 bridged and got 1.21v load and a BSOD at stock clocks. No idea what caused it but I'm removing VID 10 and hope stability returns.

[nickless]

If 2/4/ give 1.22-1.23v, can I try 2/4/10 for some extra vcore?

[off] Are commands for GTX 285 in nvflash the same like GTX280:
For Normal Flash: nvflash -5 -6 newbios.rom
For Forced Flash: nvflash -4 -5 -6 newbios.rom [off]

[NapalmV5]

I measured 1.18v at both caps to the right of where 'C1277' is written on the PCB. I may be wrong though this might not be shader voltage.

Also I just bridged VID 10 (as well as having 1/2/3/4/11 bridged) and got no change in voltage. Then I removed VID 4 leaving 1/2/3/10/11 bridged and got 1.21v load and a BSOD at stock clocks. No idea what caused it but I'm removing VID 10 and hope stability returns.

sorry about that.. after so many combos..

i had:
1/2/3/4/5/11
1/2/3/4/5/10/11
1/2/3/4/5/9/10/11
many others

i dont remember exactly how i reached ~1.25vcore

probably vid 5 so: 1/2/3/4/5/11

im gonna confirm that in a bit..

If 2/4/ give 1.22-1.23v, can I try 2/4/10 for some extra vcore?

[off] Are commands for GTX 285 in nvflash the same like GTX280:
For Normal Flash: nvflash -5 -6 newbios.rom
For Forced Flash: nvflash -4 -5 -6 newbios.rom [off]

no just 1/2/3/4/11

let me see if i can get it ~1.24-25vcore


yes same commands

[chispy]

[QUOTE=CryptiK;3640847]I was going to reply to your PM but it looks like you have it sorted now.



Hey Chispy, here's the points I use. Red = vgpu measure point, green = vmem measure point.
QUOTE]


Thanks a lot Cryptik , appreciate your help bro. Testing today i will let you know how this mod goes on my card.


chispy.

[CryptiK]

sorry about that.. after so many combos..

i had:
1/2/3/4/5/11
1/2/3/4/5/10/11
1/2/3/4/5/9/10/11
many others

i dont remember exactly how i reached ~1.25vcore

probably vid 5 so: 1/2/3/4/5/11

im gonna confirm that in a bit..




no just 1/2/3/4/11

let me see if i can get it ~1.24-25vcore


yes same commands

Don't apologise, I'd been bridging things experimenting myself, and was minutes away from bridging VID 10 of my own accord.

I tried 1/2/3/4/5/11 and it didn't cause any change in voltage for me. I'd like to get 1.25v, I think that would be a good balance between heat & speed.

Thanks a lot Cryptik , appreciate your help bro. Testing today i will let you know how this mod goes on my card.


chispy.

No problem mate, hope you get some good results with it.

[NapalmV5]

i just redid 1/2/3/4/5/11 and @ startup its ~1.24vcore and @ load ~1.25-26vcore



next ill try 1/2/3/4/5/6/11

edit: startup @ 1.23vcore load @ 1.25-26vcore

[NapalmV5]

http://www.xtremesystems.org/Forums/...2&postcount=77

fgw,

Shall do that mate and get back to you.

I just finished reading and re-reading the Intersil ISL6327CRZ multiphase closed-loop feedback and compensation PWM Voltage Reg datasheet, the VR used by NV in the die shrink G200 reference cards, GTX 260 55nm and GTX 285 55nm.
Seems NV screwed you guys over with VR cost cutting this time around, mind you the IC itself only costs $5usd or so.

It's a VR designed with cost savings and affordability in mind so it lacks any kind of external low-pin count bus interface accessibility and relies on the pcb designer to set up all the necessary operational values in design and testing phase. There are 8 VID pins which when pulled up the base VID is read by which pins are 0 or 1 and converted to digital signal by DAC. '

Voltage adjustment is done through current offset via the OFS pin, which is polarity dependant for negative or positive offset, switch to Vss (gnd) for neg, switch to Vcc (vin) for pos. Offset is configured through external resistors connected between the DAC and REF pins, the impedance dynamically controls the current which in turn determines the Vout (voltage out).

Long story short, unless NV have some kind of low pin count programmable interface to adjust a pull up or pull down resistor connected between DAC digital VID signal pin and REF voltage reference pin there is absolutely NO CHANCE AT ALL to control Voltage Adjustments via software on either the GTX 260 55nm or GTX 285 55nm. The only way would be to change the resistor between DAC and REF pins, to give a greater current offset to drive Voltage out higher.

If EVGA is saying it is possible on their cards, short of physical changes to the NV reference cards to add this basic functionality I can't see how it is possible at all. I read over the datasheet a good 4 or 5 times just to make sure I completely understood the electrical design and don't see any way to do it.

lower resistance @ the 1kohm resistor dac/ref might lead to the back of the card lowers vcore.. higher resistance doesnt allow os boot @ 1.33vcore

suggestions?


cryptik.. what you think about the 1k resistor on the back.. its the 1st resistor at the bottom right of the vid pins.. the 26.6k resistor is the 2nd one

[CryptiK]

Interesting, what do you get with just 1/2/3/4/11 ?