Sonarr Prefer X265 ((better))

Upgrade Until Score: Leave this at 0 or match your profile settings.
Score: Enter 10 (or any positive number).

To make Sonarr prefer x265 (HEVC) content over x264, you must use Custom Formats Release Profiles

Release score adjustments combine with Custom Format scores and size/quality scoring to influence selection.
Use blocking sparingly; prefer negative scoring over absolute blocks unless certain tokens are always undesirable.

Here is the paradox: Your server might work harder playing an x265 file than an x264 file. sonarr prefer x265

You don't just flip a switch. You use Release Profiles and Custom Formats. To make Sonarr prefer x265 (HEVC) content over

. If they don’t, your media server will have to "transcode" the video, which puts a massive heavy load on your CPU. Regex strings Release score adjustments combine with Custom Format scores

Assign this -10000. Then assign x265|hevc|h.265|10bit a positive +10000.

Qualities (in order from lowest to highest): SDTV / 480p / 720p / 1080p / 2160p (depending on your needs)
For the qualities where x265 is acceptable, set size limits that reflect typical x265 sizes (e.g., 1080p x265: 700 MB–4 GB; 1080p x264: 1.2 GB–6 GB). This helps Sonarr differentiate.
Cutoff: Set to the quality level you consider “final” (e.g., 1080p or 2160p).
Requirements: You cannot directly require codec, so pair with Custom Formats scoring (below).

Assign high positive scores to your x265-related formats, higher scores for x265 10-bit and HDR if you prefer those.
Assign a moderate score to x264 format (or even a negative) so x265 will outrank x264 for the same resolution.