Gamers Nexus Shunt Mod Guide for NVIDIA Titan V

Steve Burke and the gang from Gamers Nexus were one of the first hardcore tech media sites to go out and splash some cash on an NVIDIA Titan V card. Since then they’ve been pretty prolific in testing the card, exploring its PCB and the potential performance that the new Volta architecture GPU has under the hood. Today we want to highlight Steve’s efforts to get more out of the card by performing a shunt mod that helps circumnavigate NVIDIA’s GPU Boost 3.0, the company’s latest GPU clockspeed management implementation. I’ll let Steve explain:

The goal for today is to trick an nVidia GPU into drawing more power than its Boost 3.0 power budget will allow it. The theoretical result is that more power will provide greater clock stability; we won’t necessarily get better overclocks or bigger offsets, but should stabilize and flatline the frequency, which improves performance overall. Typically, Boost clock bounces around based on load and power budget or voltage. We have already eliminated the thermal checkpoint with our Hybrid mod, and must now help eliminate the power budget checkpoint. This content piece is relatively agnostic toward nVidia devices. Although we are using an nVidia Titan V graphics card, priced at $3000, the same practice of shunt resistor shorting can be applied to a 1080 Ti, 1070, 1070 Ti, or other nVidia GPUs.

“Shunts” are in-line resistors that have a known input voltage, which ultimately comes from the PCIe connectors or PCIe slot. In this case, we care about the in-line shunt resistors for the PCIe cables. The GPU knows the voltage across the shunt (12V, as it’s in-line with the power connectors), and the GPU also knows the resistance from the shunt (5mohm). By measuring the voltage drop across the shunt, the GPU can figure out how much current is being pulled, and then adjust to match power limitations accordingly. The shunt itself is not a limiter or a “dam,” but a measuring stick used to determine how much current is being used to drive the card. Shorting the shunts will effectively “trick” the card into thinking it’s pulling less current than it is, resulting in the card drawing more current still – the result is more stable clocks, as we’re bypassing power budget limitations through a hardmod.

The guide from Steve, as he mentions, is relevant for most modern NVIDIA card, not just Titan V cards, which makes a fairly valuable resource. As well the article on Gamers Nexus, there is a great accompanying video which offers a great step by step guide. Check out the video here on the Gamers Nexus YouTube channel.


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Taiwan sdougal says:

More nice work from Stevie Burke and the guys...

Brazil Rbuass says:

So we have a sensor INA3221 sensor IC (triple) in order to measure the parameters (voltage, current, power at +12V.
It using the current shunts in order to generate measurable voltage (little, but can be measured).
The graphic card control the current flow thru the Shunts.
So, the card adjust in real time the clock speed and performance to keep under specifications.
If we reduce voltage signal in the shunts (with linear dependence from current - V = Ri), will affect the power limit.
But if you use that kind of modifications, you will not provide stable, static and reliable resistance change.
Pascal are very sensible, and it has protection system to under reporting curent, and GPU can keep in low power state is reported very little resistence.
That's not the best way to improve Power Limit to the common INA3221.
You need to add fixed resistences in the 3 capacitors near the chip to do it, and you can better improve power limit.

Best wishes.

Croatia dabar_Solta says:

@rbuass yes exactly that, and even if they do shunt mods they should buy resistors and solder them not use this crappy method of applying that liquid.. also if they cant solder one smd resistor i am curious about their overclocking "expertise" and think this is all just for show but thats where oc scene is gone in last few years unfortunately.

United States GtiJason says:

Shunt Mod . . . Is that like when a male get's the surgery to become a shemale ? I think I'll stick with regular Hard Mods :p

edit: my comment is simply a silly joke and in no way represents my opinion of Steve, Der8aur or Buildzoid. I have great respect for all 3 of them and what they do

France Wimpzilla says:

GN don't know anything about electronics and physics!!!!
You are speaking about the same guy that measure T° with an IR gun on reflective surfaces claiming he is top notch thermal guy!!
What you could expect from GN aside basic stuff?!

United States PKKShadow says:

Wimpzilla said: GN don't know anything about electronics and physics!!!!
You are speaking about the same guy that measure T° with an IR gun on reflective surfaces claiming he is top notch thermal guy!!
What you could expect from GN aside basic stuff?!


Why not help the guy understand then? Email them, or send them a tweet. Yelling on a forum isn't helping.

Croatia dabar_Solta says:

ok so i got bit nervous as this is 100th time i see this kind of "mods" presented so i went to my workshop dug around my smd resistor stash and replaced 1R0 sense resistors with 3R3 i had on my asus strix gtx1050ti , soldered few extra capacitors and in half hour i was finished.
i have tested only furmark for now but card seems to be stable enough for everyday work.

i used cheap hot air rework/soldering station and cheap usb microscope camera for pictures so sry for quality.

my point is THIS is how you change resistors right way.
imgur.com/a/YsiuF
e

furmark score after mod (sry no before) : http://www.ozone3d.net/gpudb/score.php?which=507107

also not sure is performance improved or got worse thats not point that is only matter of resistor values.
imgur.com/a/ASDoo

France Wimpzilla says:

PKKShadow said: Why not help the guy understand then? Email them, or send them a tweet. Yelling on a forum isn't helping.


I tried to help them in a constructive way, but as always in these situations where you make notice some flaws to someone, people not listen and ignore you!

I posted a lot of times on their utube video, but get ignored because putting them under bad light.

Anyway for the kind of audience that GN have this kind of stuff is more than enough, i suppose!

So yeah!

Brazil Rbuass says:

Well, in my opinion, if they intend to teach and explain something, should do it with right information.
I don't follow them, but respect the intention to bring information.
But this kind of "mod", even more for a TTV, is not properly.
Good lucky for who will follow.
We will receive one TTV and do it the right way (for what I consider).

�

Czech Republic buildzoid says:

Shorting the shunts with liquid metal is Roman's idea: https://www.youtube.com/watch?v=c2_UjhMHU5o&t=235s

Unfortunately no one in the GN team has any expirience soldering anything so I told them if they want to push the card more they should just use liquid metal because that's easy to do and remove.

My prefered way of dealing with Nvidia's power monitoring circuitry is to completely disconnect the INA3221s from the shunts and then use some resistors to feed 12V and 11.995V into the INA3221's inputs. That way the card thinks it's always pulling 36W or whatever.

United States marco.is.not.80 says:

LOL... "sh!tty committee meeting adjourned!"

Brazil Rbuass says:

buildzoid said: Shorting the shunts with liquid metal is Roman's idea: https://www.youtube.com/watch?v=c2_UjhMHU5o&t=235s

Unfortunately no one in the GN team has any expirience soldering anything so I told them if they want to push the card more they should just use liquid metal because that's easy to do and remove.

My prefered way of dealing with Nvidia's power monitoring circuitry is to completely disconnect the INA3221s from the shunts and then use some resistors to feed 12V and 11.995V into the INA3221's inputs. That way the card thinks it's always pulling 36W or whatever.


Don't need to disconnect the INA 3221, but add one resistor for each capacitor near the chip (there are 3).
So, the card will not understand and thing there are less than normal, and so, will give the wall for Power Limit.

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