I was playing around with this very thing under Linux earlier this week. Unfortunately, what I don’t have is a direct Windows equivalent, but hopefully you’ll still find some of the following illuminating.
I do happen to have a FW charger, but I also have several lower-rated USB-PD sources, as well as a brand new 250W cable with a built-in realtime power draw readout (for diagnosing a different problem I’m having with my FW16).
My benchmark for the moment is “Hardspace: Shipbreaker” via Steam/Proton. It has a bug that turns out to be useful for stress testing – if the v-sync option is disabled, it just cranks out frames as fast as the system will let it*. I’m connected to an external 1080p monitor, over the dGPU’s dedicated port on the back, and with the internal screen disabled.
I have my fingers on several performance knobs, but the two that are likely to have Windows analogs are:
- The
/sys/firmware/acpi/platform_profile
– this is essentially the equivalent to your “power mode”, and lets me pick from a firmware-defined list (low-power, balanced, performance).
power_dpm_force_performance_level
for the dGPU and the iGPU. This should in theory let me change the power behavior of the two graphics providers independently of the main platform profile. In practice, it only seems to come into play if I’m using the 180W charger.
dGPU and iGPU wattages as read from amdgpu_top
’s averages for each of the devices. Battery rate from upower --dump | grep energy-rate
.
Supply |
Platform |
iGPU |
dGPU |
iGPU(W) |
dGPU(W) |
USB-C(W) |
Battery(W) |
180W FW |
Performance |
auto |
auto |
37W |
82W |
166W |
3-5W (discharging) |
180W FW |
Performance |
low |
auto |
0-2W |
50W |
165W |
50W (charging) |
180W FW |
Performance |
low |
auto |
16W |
67W |
122W |
0W (charged, stable, no remote desktop) |
180W FW |
Performance |
low |
auto |
4W |
52W |
107W |
0W (charged, stable) |
100W PD |
Performance |
auto |
auto |
60W |
48W |
84W |
6W (discharging) |
100W PD |
Performance |
low |
auto |
60W |
46W |
84W |
7W (discharging) |
60W PD |
Performance |
auto |
auto |
59W |
46W |
46W |
36W (discharging) |
60W PD |
Performance |
low |
auto |
60W |
46W |
46W |
36W (discharging) |
Unplugged |
Performance |
auto |
auto |
54W |
43W |
N/A |
84W (discharging) |
*Fortunately/unfortunately, all the entries above – except for the one labeled “no remote desktop” – had another process running that was apparently inhibiting how many frames the game could throw out (given that it does seem to be CPU bound). I suspect that in turn that suggests the above data is not representative of the maximum wattage I could be getting out of those components, vs. if I had a benchmark that could properly slam the GPU.
An additional note – the iGPU and dGPU draws are lower here in the absolute max-power scenario than they were earlier this week for me - I was reaching a continuous 98-99W (and very occasionally, breaking 100W). I’m at a loss as to why I was unable to replicate those results today. I do find it interesting that the SUM of the dGPU and iGPU in the highest-performance case seems to be 120W. I also find it interesting that the iGPU seems to be given preference - to the tune of the entire 60W power budget? - in all the scenarios where the power supply is NOT the 180W, even when the iGPU is supposedly force-set to low power. That seems like it might be a bug, and I am somewhat disappointed that I can’t seem to let the dGPU run at a nominal full-tilt, without the iGPU tagging along for the ride (and causing so much total draw that the battery gets dipped into).
That said… I have not yet found anything that actually takes as much grunt to play, as this game does in its buggy state. With the full performance settings on, and running the game with v-sync enabled at “ultra” settings, the dGPU hovers around 30W. I don’t know why the iGPU is being such a hog, when it should nominally not be involved in processing the output to the dGPU’s (nominally dedicated) port. But… that’s likely a puzzle for another day.
I think three main takeaways here are:
- Yes, the power supply matters,
- Yes, the “power mode” matters, and
- Even with the 180W supply (and its raised wattages), running totally full-tilt can still outstrip the supply and cause battery usage