Terribly slow transcode on modern Intel 265k iGPU

[nyanmisaka]

Yes, if the BIOS doesn't offer an option to disable RC6 power saving, then you could try a more recent kernel version like 6.16 or even 6.17-RC (This may require you to manually compile the kernel or update to a Linux distro that uses a rolling release.). If it still doesn't work correctly, I believe you'll have sufficient evidence to file an issue with the Intel driver repository.

- Intel Media Driver (userspace): https://github.com/intel/media-driver/issues
- Intel i915 Kernel Driver: https://gitlab.freedesktop.org/drm/i915/...=Community

Furthermore, you could install Windows 11 for comparison (Intel always does more testing on Windows, WHQL) to further rule out the hardware itself as the cause.

- Intel Windows GPU Driver: https://www.intel.com/content/www/us/en/...ndows.html

[nyanmisaka]

Another option is to try Debian 13, which uses the 6.12 LTS kernel, thus avoiding potential regressions in the 6.14 kernel used by Ubuntu.

[Jey Forey]

Another option is to try Debian 13, which uses the 6.12 LTS kernel, thus avoiding potential regressions in the 6.14 kernel used by Ubuntu.

Thanks for all your input, I've managed to get hold of an intel A380 and it's likely to arrive tomorrow which I'd like to try first rather than re-install the OS. Will evaluate my options further if that doesn't work.
Appreciate everything you've done to help out, I'll update the thread if I have more to share regarding the root cause.