GPU Power Draw at Increased Refresh Rates

tommybhoy · 30 Oct 2015 at 18:10

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?

Sin_Chase · 30 Oct 2015 at 18:15

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)

Gregster · 30 Oct 2015 at 18:17

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?

shankly1985 · 30 Oct 2015 at 18:28

I said this before, on AMD my clock speeds remain at 2d no matter the refresh rate while idle.. 300/150

Silent_Scone · 30 Oct 2015 at 18:30

Really most of that is fairly obvious even to the layman.

Higher refresh rate > Higher framerate > increased computing > increased power consumption > increased thermal output > cue I need to go water, but I'll go hybrid instead > Ok I should have gone for a full loop > I've gone for a full loop > Air sucks, I hate the things you have.

LoadsaMoney · 30 Oct 2015 at 18:42

On my old Asus 144Hz monitor through HDMI, my memory clock used to run @ full whack on idle, 1250Mhz (290X), but when i changed to the BenQ XL2730Z 144Hz, using DP, it didn't, it stayed at its norm 150MHz while idle.

humbug · 30 Oct 2015 at 19:01

Thats interesting.

Dygaza · 30 Oct 2015 at 19:53

Looking at Fury's chart. Maybe AMD has even too high idle clocks on 2D. Could save some lower idle consumption with lower clocks. Then again I'm sure there is reason for those clocks. Perhaps you start having other problems with even lower clocks.

tommybhoy · 30 Oct 2015 at 20:13

Sin_Chase said:
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)

Gregster said:
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?

artur_k · 30 Oct 2015 at 20:59

Dygaza said:
Looking at Fury's chart. Maybe AMD has even too high idle clocks on 2D. Could save some lower idle consumption with lower clocks. Then again I'm sure there is reason for those clocks. Perhaps you start having other problems with even lower clocks.

I've seen somebody on another forum running 290x 75Mhz core and 100mhz mem with modified bios
I think he was trying to go lower but I don't know how low it ended before it was unstable

bru · 30 Oct 2015 at 21:04

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.

r7slayer · 30 Oct 2015 at 21:12

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.

tommybhoy · 30 Oct 2015 at 23:14

bru said:
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?

r7slayer said:
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.

whyscotty · 30 Oct 2015 at 23:20

tommybhoy 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?

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

Rroff · 30 Oct 2015 at 23:26

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

tommybhoy · 30 Oct 2015 at 23:38

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

Thanks neil.

Rroff said:
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.

Rroff · 30 Oct 2015 at 23:47

Can (or used to be able to) change the different power state clocks in the firmware and reflash it using nibitor, etc. (not that I'd recommend doing that unless you know what you are doing).

Quartz · 31 Oct 2015 at 13:31

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

You get the same increase in power usage if you plug in more than two monitors.

stulid · 7 Nov 2015 at 20:14

Update.

http://www.pcper.com/news/Graphics-...wer-Increases-High-Refresh-Rates-Promises-Fix

r7slayer · 7 Nov 2015 at 20:29

stulid said:
Update.

http://www.pcper.com/news/Graphics-...wer-Increases-High-Refresh-Rates-Promises-Fix

Good stuff!