GPU Power Draw at Increased Refresh Rates

[tommybhoy]

PcPer released an interesting article about increased power draw with high refresh rates.

At 60Hz refresh rate, the monitor was drawing just 22.1 watts while the entire testing system was idling at 73.7 watts. (Note: the display was set to its post-calibration brightness of just 31.) Moving up to 100Hz and 120Hz saw very minor increases in power consumption from both the system and monitor.

But the jump to 144Hz is much more dramatic – idle system power jumps from 76 watts to almost 134 watts – an increase of 57 watts! Monitor power only increased by 1 watt at that transition though. At 165Hz we see another small increase, bringing the system power up to 137.8 watts.

Interestingly we did find that the system would repeatedly jump to as much as 200+ watts of idle power draw for 30 seconds at time and then drop back down to the 135-140 watt area for a few minutes. It was repeatable and very measurable.

http://www.pcper.com/news/Graphics-...raw-Increased-Refresh-Rates-using-ASUS-PG279Q



Afaik, according to the article it's Nvidia specific, as my clocks sit at a static 135MHz@144Hz, can't see how it would draw more power at those clocks myself, anyone tested this out@165Hz to see if their clocks do increase?

 

[tommybhoy]

Larger resolutions/refresh rates will require a higher 2D clock to drive. This will increase power usage. It's a simple matter of numerical fact.

Interestingly using different connection ports for multiple monitors (EG - HDMI and DP) will also increase clocks over using two connections of the same type (EG - DVI and DVI)

I set my 2D clocks for 120Hz so as to keep lower power. I thought anyone with half a scooby would know this or not?

Multiple Displays using DP and HDMI:

Clocks same as single screen, Gpuz showing 135MHz too, something I'm missing?

 

[tommybhoy]

Watched the PCPER podcast and they mentioned that it only does it on the GSYNC screen or some thing like that. Would have to go back and check what they actually said.

I'm running 144Hz G-Sync and not getting increased clocks though, that's why I originally asked, perhaps it only happens on big Maxwell?

Interesting read. It doesn't have the same effect on the AMD card as it does nvidia. I asked this before it it only effects nvidia cards and it appear it does as i don't have this problem either. It seems you have to set it at 120Hz or lower on the desktop to try and prevent the card ramping up its frequency as much. Seen lots of users complaining about high idle temps on nvidia cards.

Perhaps it depends what variant/bios/monitor using AMD you are running as LoadsaMoney had high clocks on one monitor but not the other one he used.

 

[tommybhoy]

My clocks increase when using 144hz G-sync or not (980ti)

Thanks neil.

It will also depend on what settings you have for multi-display/mixed-GPU acceleration and power management mode in the nVidia control panel.

As I've got an additional 5" display hooked up for diagnostics with some settings it always stays at low power 3D clocks regardless :S

Default Multiple display performance mode and Adaptive power mode.

Thanks Rroff.