Hi,
i am currently using a RX 5600 XT but due to newer games like Baldurs Gate 3 only running at 30 fps with low settings i am looking for a new card.
My specs are:
CPU: 5800X3D
GPU: 5600 XT
RAM: 32gb 3200 mhz ECC
Mainboard: Asrock B550 Extreme 4
Power Supply: BeQuiet 650W
Due to the high energy prices in my country i have to also look a the idle power draw of the card since the GPU is basically idle for 8-10 hours while i work and play maybe 1-3 hours in the evening.
I am looking at the 7800XT and 6800 (non XT) but i can’t find any info on the idle power draw in Linux with two monitors connected (2x 1440p 100Hz).
I have read that the 7900 series uses 80-100 W with two monitors connected in Linux, though the information is almost a year old and i am hoping that the situation has improved over time.
Are there any 7800XT owners here who run Linux and can give me some insight on the power draw?
I find 80~100w for the card alone hard to believe. My 6700xt self reports as under 30w idle.
There’s a lot of improvement to be made there, though; memory doesn’t clock down unless you use a single 60hz display in linux. Allegedly… 6.6 or 6.7 kernel should possibly improve this to some degree, along with using variable refresh to clock down, but those don’t exist yet. I don’t know of any practical way to force memory clocks that works either, as the driver seems to block manual memory clock adjustment on the fly, though it sometimes breaks resulting in heavy screen flickering as the memory clock bounces up and down ignoring the screen refresh.
Total system power idle with a 5900x on x570 and 6700xt, as well as a M.2 that idles at 8w, a boatload of sata ssds, and a lot of fans, seem to be around 100w.
Most of your idle power on Radeon with high refresh is going to come down to memory not idling, so I could see 50w being possible for idle on a 16gb gpu with particularly driven gpu memory.
You might be able to underclock the memory manually/perpetually to drop idle power, but clocking it back up to game isn’t really working, at least on 6000 series, and it will impact performance. Memory bandwidth is super constrained on modern GPUs.
On Windows the 7900 series idles around 33 W with two 144hz displays but there were some teething issues on Linux when they were launched, thus my question.
I have a 6950XT with three 1080p60 monitors attached to it.
The combined desktop setup has an area of 3000x2160 pixels.
Since upgrading to debian 12 (kernel 6.1.55, Mesa 22.3.6) I idle at about 17W on an empty desktop.
While running a light load like a web-browser on two screens, it uses about 28-30W.
The shader clock reports to be around 40MHz when idle, and the memory clock around 330MHz.
Under a heavy load like a GLSL ray-tracer or Unigen Superposition, it consumes around 260-300W, but most moderate loads will only consume about 100W with this particular card.
The Navi cards are VERY picky about the monitors attached to them, and may even be affected by which cable interface you use (HDMI vs DisplayPort).
AFAIK there might be a fix for certain monitors by changing the modeline for the xrandr config, but I don’t have any way to test that myself.
EDIT: I measured the PSU consumption for just my tower with two browser windows open, and it measured 90W.
This is with a 3900X, X570 M/B, 2 DDR4 sticks, 1 NVME drive, 1 SATA SSD, and 1 3.5" HDD.
The lowest power consumption I’ve seen is around 60W from the PSU.
I think there was a driver bug that got resolved in latest kernel(s). So good news is, 33W should be the norm now even on Linux. You might need to install a newer kernel though, any distro version released in 2H of 2023 should be fine.
According to Phoronix the 7800 XT seems to mostly hover around 200W but with a 30W idle. The 7700 XT seems to be averaging 150W, but you do lose ~15% performance, too.
Get some measurement before you start tweaking things and updating kernel.
Your are not the first one to encounter power state bugs with multiple monitors and high refresh rates, even nvidia had them.
If your monitors support it, try enabling Variable Refresh Rate, it supposedly helps a lot with radeon 7000 series. Third party measurement before after turning VRR on:
Either way, modern gpus should clock down to 10-25W depending on idle load. My nvidia 2070S cosumes 20W when idle on 4k120Hz monitor, withour VRR. I use DP1.2 → HDMI 2.1 active convertor that craps out with VRR/GSYNC-lite enabled.
Thank you for the input, i have bought myself a 6800 since it was on sale for 360€ today.
Hopefully this card lasts me at least three years, maybe by then the GPU market will look a bit better with more competition.
Small update for those interested.
With two 1440p monitors set to 60 Hz, both connected via Display Port:
7-10W idle with 1-3 remote clients on one monitor and Firefox on the other, 20 W with mouse movement
35W with a Youtube video playing
2x 1440p 75-144 Hz
45-50W independent of monitor content excluding games
With Kernel 6.5.11 and Mesa 23.2.1 memory down clocking only works at 60 Hz, neither above or below.
If one monitor is connected via HDMI and the other DP the memory doesn’t clock down correctly and stays at maximum frequency.
Update on my side. Recent updates got me some changes in controlling clock speeds. Reason for high idle power was memory clock running at full speed 100% (1250MHz) of the time.
Manually lowering it is now possible with CoreCtrl and I’m now at 35W idle. 22W with display powered off.
Seems like the influx of new Radeon 7000 models finally made AMD to “optimize” some stuff.
