Power Consumption: Idle (2D Desktop)
Unfortunately, AMD doesn’t fare very well here. We’ve repeated these measurements, reviewed running processes, and even switched systems altogether. We just couldn’t get the Gigabyte Windforce Radeon R9 285 to draw less than 15 W at idle.

Looking at just one minute’s worth of power draw curve after smoothing it over a bit, it’s plain to see that there are significant fluctuations even at almost 0 percent load.
The situation at the motherboard slot looks perfect. We never exceeded or even reached 75 Watts.
Let’s take a look at how that 15 W idle draw is distributed:
| Minimum | Maximum | Average | |
|---|---|---|---|
| PCIe 12V | 2 W | 21 W | 8 W |
| Motherboard 3.3V | 1 W | 3 W | 2 W |
| Motherboard 12V | 0 W | 31 W | 5 W |
| Graphics Card Total | 2 W | 45 W | 15 W |
List of All Individual Values per Supply Line
For those readers who like lots of detail, we’ve put together all of the idle power consumption values for each supply line in the gallery below:
Voltages
The voltage values are very important because they’re used to calculate power consumption by multiplying them with the amount of current. Looking at the 12 V rail, we see very clearly that the voltage fluctuates extremely if measured in small increments of time. The average voltage is 12 V, but the switched-mode power supply architecture and the different phases of capacitor load leave a very distinct mark. We’d like to tease our reference article about current graphics cards in relation to common power supply units here, which will cover how the two interact in detail. This is a much more interesting topic than it might appear to be at first glance.
We don’t know yet if the high idle power draw represents a problem in our specific board partner’s card or if it’s a problem inherent in the Tonga architecture. Comparing reviews proves difficult once again in light of the scarcity of actual homogenous reference cards. This is too bad, since we’d have liked the Radeon R9 285 to provide a stronger showing in this arena.
|
|
|
|
|
- The Radeon's GCN Is Updated Again: The Tonga GPU
- Asus Strix Radeon R9 285
- Gigabyte R9 285 WindForce OC
- Test Setup and Benchmark Suite
- Synthetic Benchmark Results
- Titanfall and Battlefield 4 Results
- Thief and Arma 3 Results
- Grid Autosport and Assassin's Creed IV Results
- Watch Dogs and Far Cry 3 Results
- Idle Power Consumption Results
- Gaming Power Consumption Results
- GPGPU Power Consumption Results
- Temperature and Noise Results
- Radeon R9 285 Holds its Own at $250



Good to see AMD have tackled the noise and temperature issues that have plagued it's previous 28nm cards as well but it's a bit late in the day given that 20nm shouldn't be to far off now.
Also, on the last page, you guys wrote R7 270X instead of R9, and in the chart it says "Relative to Radeon HD 7950 Boost". Oh, and in the Pros section, it says the 285 has R9 260 like performance?
[EDIT by Cleeve]
Thanks for the proofread, fixing it now!
[/edit]
I prefer get a r9 280 and downclock get same results. I can't see the point of this heat on graphics. maybe drivers. OR THIS IS HAWAII XT! Too much Heat!
I think the guys see if they hit the OC the room Will burn! maybe a problem with drivers.
Last time i see that Heat 290x tests. lol!
But in fact, the memory interface was cut by a third (384 bit -> 256 bit), not half.
[Edit by Cleeve]
Good point, fixed! Thx.
[/edit]
[Edit by Cleeve]
Good catch, fixed but might take a while to populate.
[/Edit]
Faster memory would have helped but more would not have made much of a difference: most of the extra memory on GPUs with more memory channels gets filled with extra copies of resources to improve availability. Without those extra channels, filling more RAM with extra copies would make little difference.
The R7 265 is faster than the R7 260X, yet the R9 285 is slower than the R9 280X?
The R7 265 is faster than the R7 260X, yet the R9 285 is slower than the R9 280X?
Yea this should have been named 275 or 275x.
The 280X probably should have been the 285, and this card should have been released as the 280X. Or it could be next-gen; call it the 380 or 375.
The 270/280 are just rehashes of HD7xxx designs while the 285 is a cut-down 290... and the 285 does beat the 280 enough times to earn its place in the 28x range.
Give the 285 a 6GT/s memory interface and it would slot in more solidly between the 280 and 280X.
The R7 265 is faster than the R7 260X, yet the R9 285 is slower than the R9 280X?
Indeed, naming schemes are always kind of bogus.
260< 260X < 265
280<=285< 280X
That's just the way it is.