Power Limit Mod had no effect!

[Jonathanese]

I have a GTX 1070 ROG Strix.

It idles at ~40% power usage, which already seems really high. During testing on something like Kombustor, it spends most of its time at the power limit. It is set to 120% but throttles at ~103%

so using a bit of conductonaut from my 8700K delid, I figured I would give the power limit mod a go.

I coated the two shunt resistors (2mOhm and 5mOhm), booted it up. Absolutely no effect.

So I tried globbing solder to short the resistors entirely. I figure if I create a power fault, I could backtrack from there. Exact same numbers. 40% at idle. throttling easily.

So finally, I completely removed both shunt resistors and bought some 1mOhm resistors to replace them.


EXACT. SAME. NUMBERS. This is not physically possible. Unless all my power is being drawn from the PCI-E slot and I'm not getting power to the molex connector. (That's the only shunt I didn't replace)

Anyone got an idea? I'm clueless.

 

[KeelinTy]

If you want to go over your stock power limit, I would suggest a custom bios, Ive made my own a few times with my 980tis and could set the power limit to whatever the hell I wanted, typically 140% since 980ti yeah. If you do a custom bios for the 1070 you should be able to get more overclocks because of a higher core voltage and a higher power limit

 

[Jonathanese]

Ah, I see you still have a Maxwell card.

For Pascal cards, the BIOS is encrypted. The card has been out for 2 years and nobody has been able to mod the bios like I've done with every card since my 9800GTX+. So I've gone to hardware modifications, which as you can see above, have had no effect.

 

[RememberThe5th]

Do you use single line with 6+8 or 2 seperate lines 1x6 and 1x8 for example?

I dont know which connectors does the 1070 require.

 

[Jonathanese]

It's a single 8-pin molex.

 

[KeelinTy]

Hmmm. Well, the 40% usage could be caused by your display, what's your res and refresh? How are your temps and temp limit?

 

[RememberThe5th]

Post gpuz screenshot.
I never exceeded 90% with 1050ti with 6pin connector, even tho max was 125% on power limit, I wish I could do the shunt mod

 

[Jonathanese]

Sorry, I posted this on another forum as well and got the idle usage problem resolved.

For those lurking, I had to use Nvidia Inspector to enable "multi-display power-save" or something like that. My displays were forcing my clocks high. After implementing the fix, I see more like 2% at idle.

But otherwise, the point is that replacing a 5mOhm and 2mOhm shunt resistor with 1mOhm shunt resistors should have see such a large *apparent* power drop that the card could have gone into power fault. Instead I saw basically no change whatsoever.

The power control on these cards read the current power usage by looking at the voltage drop across a shunt. It reads the input voltage (12v) and read the voltag drop on the shunt to determine the current (V=IR), then multiplies the two to determine what the current power usage is.

This means that with a shunt resistor with 1/5th the resistance, the device should be seeing 1/5th the power usage. If I'm drawing 100W, it should think I'm only drawing 20W. The fact that these numbers have not changed is a physical impossibility unless there is something I'm missing. I'm trying to find out what I'm missing.