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post #5 of (permalink) Old 03-21-2019, 12:37 AM - Thread Starter
chrcoluk
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Quote: Originally Posted by Zfast4y0u View Post
you mean, your clock speeds gets lower? like in steps of -13mhz? thats normal, cause ur gpu temp goes up, so card clock down a bit, to hold temps in check.
No I specifically stated the clock speed does not decrease.

I will try and explain it again in as simple terms as possible.

When boost works normally and hit power limit this is what usually happens.

Power limit shown by software is close to power limit set on card so e.g. if set to 120% you would see 110-120%.
Clock speed reduces to reduce power load to stay within limit.

Right?

Thats not whats happening.

Instead power usage reported by software shows much much lower than the limit, it doesnt happen immediatly it takes several hours to start happening.

So e.g. if limit set to 120% it will top out at about 70%.
Clock speed will stay at max speed.
But performance will drop.

Basically the 100% utilisation is at a lower level, maybe some of the cuda cores get disabled or something to reduce the power draw, and performance whilst not reducing clock speed.

Understand now?

So e.g. when this occurs I get 50-150fps in unigine heaven, but then I reboot to bring back proper behaviour I get 250fps. Division 2 works flawless 60fps 60-90% load when card works properly, when it starts occurring I get screen tearing as it then cant sustain 60fps even in simple scenes and lower resolution. I have to reboot to restore proper behaviour.

My thoery is the card is detecting lack of capability from the psu possibly (so I am inclined to think yes I need a bigger psu, I was already aware of psu limitation when getting the card which is why I dont set the max 150% limit), and there is some kind of programming on the card that when this is detected it disables a chunk of the cores, as the only rational explanation for what I am seeing is less cores are active, same clock speed, but lower power usage and performance.

I wanted to be absolutely sure tho because changing the PSU is a massive pain in the backside. Its also a fair chunk of change to pay for it as well and if I am wrong its a lot of money to lose on a theory.

This profile is 1.031v 1974mhz 120% power limit, which I think on the card is a 300watt limit.
When I use my low power profile for weaker games I set the limit to 90% so 225 watt limit, and that uses 0.875v for 1846mhz. That profile doesnt get the problem.

The 12v rail has 480 watts capacity so headroom should be there.

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Last edited by chrcoluk; 03-21-2019 at 12:51 AM.
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