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NeoTheFox

Member

Registered: 2015-11-17

Posts: 14

[SOLVED] Hybrid graphics producing backward results on ThinkPak e490

I'm a bit stumped here and looking for at least a nudge in a right direction.
My  E490 has RX550 GPU and an intel iGPU, and when I'm trying to use the RX550 for games it produces worse results than the iGPU with huge lag spikes happening at semi-regular intervals.
I've been trying to pinpoint the problem for 2 days now.

At first I tried to eliminate as many variables as I could, so I upgraded the on-board firmware for a much more recent one, without any luck.
Then I've tried using GNOME on Xorg, GNOME on Wayland and Sway - no change.
Next thing I've done is installed amdvlk - no change in Vulkan applications, performs roughly the same as RADV/ACO

So I decided to run some benchmarks and test things. Running Unigine Superposition I got no lag spikes and an expected result of the iGPU being roughly 2 times slower than the RX550. But due to the relatively heavy nature of the Superposition it ran at 4-7 FPS on Intel and at 13-15 FPS on Radeon.
This got me thinking why the lag spikes don't happen during the benchmark, luckily I own a game made in the same engine - Cradle.
Playing Cradle, once again, produces lag spikes, but from that point on I decided to use Cradle exclusively as my testing game.

With Radeon I get huge lag spikes every 2-3 seconds, FPS is closer to 50 but it constantly drops to sub 20. Having previous experience with using an eGPU on X230 via an adapter I remembered that the link between the GPUs and the system was the main limiting factor for me then, and I decided to measure the bandwidth there.

Running glxgears with vblank_mode=0 produces these results:

➜  ~ glxgears
ATTENTION: default value of option vblank_mode overridden by environment.
48079 frames in 5.0 seconds = 9615.628 FPS
49048 frames in 5.0 seconds = 9809.531 FPS
XIO:  fatal IO error 62 (Timer expired) on X server ":0"
      after 101432 requests (79 known processed) with 0 events remaining.
➜  ~ DRI_PRIME=1 glxgears
ATTENTION: default value of option vblank_mode overridden by environment.
13527 frames in 5.0 seconds = 2705.329 FPS
13619 frames in 5.0 seconds = 2723.593 FPS
X connection to :0 broken (explicit kill or server shutdown).

First one being Intel, second one being Radeon

And now I don't know where to look next or how to resolve this bottleneck. Some other things I've tried that wasn't worth mentioning before - gamemode, different scheduling, -ck kernel, regular kernel, running Steam with DRI_PRIME=1, schedtool.

I would really appreciate any help with this!

UPDATE: Turns out the hardware just sucks. The GPU was throttling and overheating, the spikes were caused by it's poor thermal handling and they can be dealt with by adjusting the power limits and powerplay tables, however I would advice anyone potentially reading this from getting this laptop. I'll be returning mine.

Last edited by NeoTheFox (2020-07-13 09:51:09)