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View Full Version : GTX260 OCP modification


massman
07-06-2009, 04:45 AM
Hey,

I don't know where I got this from or who made this picture, but here's the confirmed working OCP modification for the reference GTX260 cards.

http://i154.photobucket.com/albums/s261/Massman-/des.jpg

Solder a 50k ohm resistor between both red points. Default would be 37k, but you'll need at least 25k ohm to go beyond 1.25v. Possibly even lower for 1.3v. At home I could boot easily at 1.65v on air cooling.

Always remember: OCP is not only triggered by voltage, but also by frequency. So, if you run 1.35v at stock clocks it might not be triggered but 1.3v and 1GHz clock might trigger it. Spending time figuring out the scaling of voltage/clocks/ocp is not a bad choice ;-)
crio
07-07-2009, 12:23 AM
Nice man.Many thanks for sharing.Can you also post the voltmod??
massman
07-07-2009, 01:35 AM
That modification is identical to the GTX280:

http://www.pcgameshardware.com/screenshots/medium/2008/06/Vmod_GTX280_01.png
largon
07-07-2009, 02:43 AM
Interesting. =)

Core VRM make-up on HD4890 (2×VT1165SF and 1×VT1195SF all parallel) makes me suspect there should be a way to independently adjust OCP triggers of each of Volterra slave regulators and not just the "global" trigger on the controller.

And, this mod should be directly applicable to HD4800 series to circumvent the famous OCCT GPU test OCP crash.
cowie
07-07-2009, 04:31 AM
not to make it to simple but since its 37k i could just pencil that down right?
massman
07-07-2009, 04:48 AM
37k is too much ... you won't be able to hit 1G.
S_A_V
07-07-2009, 11:19 AM
:banana: :banana: :banana:
Thx a lot massman!
largon
07-08-2009, 04:55 AM
And just for clarification; this mod applies only to the original/old/first revision of GTX260 with Volterra VRM "digital PWM".
massman
07-08-2009, 06:29 AM
To the VT1165 controller, I presume.

I didn't figure this one out myself, so don't ask too many technical questions. I haven't seen any datasheet of this IC.
TheKarmakazi
07-08-2009, 10:17 AM
Time to extrapolate where it would be for GTX295 now...
Stelios
09-23-2009, 09:44 AM
Anyone found the dual pcb gtx295 points for ocp mod ???
Vivi
10-13-2009, 12:56 PM
dieng for a vMem mod >_<. these cards already own with stock volts, imagine vmodded mem!
Vivi
10-19-2009, 01:05 AM
that spot reads 370k pieter :O. i know you know nothing of the mod, but has it been tested?
massman
10-19-2009, 03:23 AM
The modification most definitly works ... as you can see from the 1GHz results at GOOC WW ;)
BAGR_001
10-20-2009, 04:05 AM
Which regulator is on this GTX 260 card? VT1165SF or different?
massman
10-20-2009, 04:31 AM
Vt1165mf
PizzaMan
01-24-2010, 12:21 AM
Hey,

I don't know where I got this from or who made this picture, but here's the confirmed working OCP modification for the reference GTX260 cards.

http://i154.photobucket.com/albums/s261/Massman-/des.jpg

Solder a 50k ohm resistor between both red points. Default would be 37k, but you'll need at least 25k ohm to go beyond 1.25v. Possibly even lower for 1.3v. At home I could boot easily at 1.65v on air cooling.

Always remember: OCP is not only triggered by voltage, but also by frequency. So, if you run 1.35v at stock clocks it might not be triggered but 1.3v and 1GHz clock might trigger it. Spending time figuring out the scaling of voltage/clocks/ocp is not a bad choice ;-)

Can you tell me which pin of the IC, the OCP mod point is connected to?
madmax999
02-02-2010, 06:08 AM
Can you tell me which pin of the IC, the OCP mod point is connected to?

Yeah, i'm interested in that too.
Which pin's on IC are for OVP and OCP mods (what are their labels)?
My opinion is that on every IC are the same labels... Am i right?
massman
02-11-2010, 01:39 AM
Don't have the card with me anymore, but I'm pretty sure it's the one on the far right in the upper row of pins.

If the controller is the same, the pinout is the same.
madmax999
02-11-2010, 02:00 AM
Thank you for your reply massman. I also thought that it's one of the pins in the right upper corner because of the marked resistor.

Do you maybe have datasheet of the VT1165MF?
massman
02-11-2010, 02:23 AM
The datasheet is under NDA.
madmax999
02-11-2010, 02:30 AM
That's just... :( :(
ReverendMaynard
02-11-2010, 07:18 AM
Is the NDA infinite? It's been around for how long now? lol
PizzaMan
02-11-2010, 07:24 AM
Someone else has already pointed me in the right direction.

http://img109.imageshack.us/img109/4945/5870ocpinstructions.jpg
massman
02-11-2010, 07:49 AM
Is the NDA infinite? It's been around for how long now? lol

I guess it'll last untill the technology is not worth protecting anymore.
[AK]Zip
03-02-2010, 02:40 PM
Does this work on the Core 216 as well?
der8auer
03-18-2010, 11:24 AM
Jep. Tested it on XFX GTX260 Black Edition 65nm 216SP