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Power Consumption In Detail

Nvidia GeForce GTX 970 And 980 Review: Maximum Maxwell
By , Igor Wallossek

Idle Power Consumption

There’s a huge difference between the two Gigabyte graphics cards. Nvidia’s reference board is almost exactly in the middle between them. The GTX 980 WindForce OC gives us our baseline by idling just under 10 W, while the derivative 970 consumes almost 20 W. This (relatively) massive difference was measured on the same platform using the same measurement methodology. Nvidia’s reference graphics card comes in at 16 W, right between the Gigabyte boards.

Our best guess is that Gigabyte has a “golden sample” at work here. But it goes to show what could be possible from Maxwell if production is refined further. We weren’t able to get our hands on a reference Nvidia GeForce GTX 970, so we had to use a downclocked version of a board partner’s card instead.

Power Consumption at Idle
Gigabyte GTX 980
Windforce OC
GeForce GTX 980
Reference
GeForce GTX 970
Reference (Emulated)
Gigabyte GTX 970
Windforce OC
PCIe Total3.99 W
3.78 W
4.52 W4.56 W
Motherboard 3.3 V0.18 W
1.93 W1.32 W1.32 W
Motherboard 12 V5.05 W
10.05 W
13.50 W 13.56 W
Total 9.22 W
15.76 W 19.34 W 19.44 W

Gaming Power Consumption

These findings further illustrate what we said on the previous page about Maxwell and its ability to regulate GPU voltage faster and more precisely. The gaming-based power consumption numbers show just how much efficiency can be increased if the graphics card matches how much power is drawn to the actual load needed. The version of the GeForce GTX 980 that comes overclocked straight from the factory manages to use significantly less power than the reference version, while offering six percent more performance at the same time.

Power Consumption while Gaming
Gigabyte GTX 980
Windforce OC
GeForce GTX 980
Reference
GeForce GTX 970
Reference (Emulated)
Gigabyte GTX 970
Windforce OC
PCIe Total137.38 W
143.85 W
122.31 W
132.70 W
Motherboard 3.3 V1.07 W 2.81 W 2.19 W 2.27 W
Motherboard 12 V34.98 W39.04 W 43.37 W 42.84 W
VGA Card Total173.43 W 185.70 W 167.87 W 177.81 W

Let’s take a look at the measurements in detail. The large load fluctuations are plain to see.

Nvidia GeForce GTX 980 Reference Card Measurement Results and Graphs

Gigabyte GTX 980 WindForce OC Measurement Results and Graphs

Gigabyte GTX 970 WindForce OC Measurement Results and Graphs

Stress Test Power Consumption

If the load is held constant, then the lower power consumption measurements vanish immediately. There’s nothing for GPU Boost to adjust, since the highest possible voltage is needed continuously. Nvidia's stated TDP becomes a distant dream. In fact, if you compare the GeForce GTX 980’s power consumption to an overclocked GeForce GTX Titan Black, there really aren’t any differences between them. This is further evidence supporting our assertion that the new graphics card’s increased efficiency is largely attributable to better load adjustment and matching.

Power Consumption Under Max. Load
Gigabyte GTX 980
Windforce OC
GeForce GTX 980
Reference
GeForce GTX 970
Reference (Emulated)
Gigabyte GTX 970
Windforce OC
PCIe Total237.63 W
233.64 W
188.96 W
192.46 W
Motherboard 3.3 V0.98 W2.63 W 2.16 W 2.15 W
Motherboard 12 V41.07 W 48.35 W
48.38 W 48.36 W
VGA Card Total279.68 W 284.62 W239.50 W 242.97 W

The values above have potential consequences for the everyday operation of these graphics cards, as they represent what can be expected when running performance-hungry compute-oriented applications optimized for CUDA and OpenCL. The reference card’s two 6-pin PCIe power connectors start looking a bit out of place in this context, as they might just not be enough.

Finally, let’s take a look at the detailed measurements. The much smaller load adjustments are illustrated graphically below. Pay particular attention to the reference card’s small drops when it hits the thermal limit.

Nvidia GeForce GTX 980 Reference Card Measurement Results and Graphs

Gigabyte GTX 980 WindForce OC Measurement Results and Graphs

Gigabyte GTX 970 WindForce OC Measurement Results and Graphs

Maxwell’s performance can almost be compared to that of a compression tool. Already compressed data (our compute-heavy numbers) can’t be compressed any further, whereas text (games) can be compressed massively.

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  • 0 Hide
    Ce3in , 19 September 2014 13:24
    Excellent Review!

    Looks like The Gtx 980 will become a part of my build family!
  • 0 Hide
    HEXiT , 19 September 2014 20:31
    went to buy 1 form ocuk today as they had around 70 in stock of both the 970 and 980... but by the time i sorted the order (about 10 mis) they were out of stock...
    so roll on next week and hopefully they will have them back in stock...
  • 1 Hide
    Marco Washa , 20 September 2014 06:09
    These cards are really impressive. GG nVidia you have done right this time.
    -Top performance as always
    -Low power consumption
    -A right price this time XD
  • 2 Hide
    Marco Washa , 20 September 2014 06:12
    These cards are really impressive. GG nVidia you have done right this time.
    -Top performance as always
    -Low power consumption
    -A right price this time XD
  • 0 Hide
    shaunwil , 20 September 2014 09:47
    Bought a 980 from scan. By 2pm they had sold almost 300 cards in the day. Looking forward to 4k G-sync with the card now when the monitor comes available.
  • 0 Hide
    Omar101 , 21 September 2014 22:51

    nvidia
  • 0 Hide
    Alpha3031 , 22 September 2014 05:00
    Now, if AMD actually made some progress with power. That should drive prices down too.
  • 0 Hide
    Mahisse , 22 September 2014 11:42
    I fear this may be the beginning of the end for AMD GPU. Seems like Nvidia is beating AMD on any entry level now with a better cost/performance ratio. I want competition not monopoly!
  • 0 Hide
    Alpha3031 , 23 September 2014 03:15
    Triple post?
  • 0 Hide
    Mahisse , 23 September 2014 09:30
    Don't know how that happened but they are deleted now :) 
  • 0 Hide
    Bitty , 9 October 2014 14:51
    Just getting back into gaming after a huge gap. Got a Gigabyte G1 gtx970 (another later) to replace a very well-behaved AMD 9790 GHz. All seemed ok until I hit replay in Grid2 when it froze. Repeatedly it did this with oc or not but temps etc were fine. hmmmmm. Valley worked like a charm with none and big overclocks - no artifacts. Titanfall would freeze too. Asetto Corsa was fine. I looked about and saw a few complaining of similar issues thinking the 344.16 drivers were the cause. I suspec ted that power might be an issue since other factors were okay and not everybody has the issue. I then found this article on power draw and the penny dropped.

    I have an oldish Antec TP New Series 650 watt modular psu. I had the gtx970 on one 25A 12v rail feeding the 8+6 connectors. It seems this was possibly not enough to cope with the peaks. Not up on psus but with 80% efficiency that 25x12 is not a full 300 watts - more like 240watts. So, I added another 12v rail for the 6pin and hey presto it worked fine no issue.

    So anyone with such an issue might try this or get a more powerful psu.
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