https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96337
--- Comment #8 from Jan Hubicka <hubicka at gcc dot gnu.org> --- This is the built withour release flags override as seems to be done by phoronix: GCC 9: y4m [info]: 1920x1080 fps 30/1 i420p8 frames 0 - 599 of 600 raw [info]: output file: /dev/null x265 [info]: HEVC encoder version 3.1.2+1-76650bab70f9 x265 [info]: build info [Linux][GCC 9.3.1][64 bit][noasm] 8bit x265 [info]: using cpu capabilities: none! x265 [info]: Main profile, Level-4 (Main tier) x265 [info]: Thread pool created using 4 threads x265 [info]: Slices : 1 x265 [info]: frame threads / pool features : 2 / wpp(17 rows) x265 [info]: Coding QT: max CU size, min CU size : 64 / 8 x265 [info]: Residual QT: max TU size, max depth : 32 / 1 inter / 1 intra x265 [info]: ME / range / subpel / merge : hex / 57 / 2 / 3 x265 [info]: Keyframe min / max / scenecut / bias: 25 / 250 / 40 / 5.00 x265 [info]: Lookahead / bframes / badapt : 20 / 4 / 2 x265 [info]: b-pyramid / weightp / weightb : 1 / 1 / 0 x265 [info]: References / ref-limit cu / depth : 3 / off / on x265 [info]: AQ: mode / str / qg-size / cu-tree : 2 / 1.0 / 32 / 1 x265 [info]: Rate Control / qCompress : CRF-28.0 / 0.60 x265 [info]: tools: rd=3 psy-rd=2.00 early-skip rskip signhide tmvp b-intra x265 [info]: tools: strong-intra-smoothing lslices=6 deblock sao x265 [info]: frame I: 3, Avg QP:27.57 kb/s: 14018.64 x265 [info]: frame P: 146, Avg QP:28.84 kb/s: 4313.98 x265 [info]: frame B: 451, Avg QP:35.29 kb/s: 204.06 x265 [info]: Weighted P-Frames: Y:0.0% UV:0.0% x265 [info]: consecutive B-frames: 0.7% 0.0% 0.0% 94.6% 4.7% encoded 600 frames in 171.30s (3.50 fps), 1273.22 kb/s, Avg QP:33.68 599.58user 1.62system 2:51.33elapsed 350%CPU (0avgtext+0avgdata 416976maxresident)k 225384inputs+0outputs (0major+95380minor)pagefaults 0swaps GCC 10: y4m [info]: 1920x1080 fps 30/1 i420p8 frames 0 - 599 of 600 raw [info]: output file: /dev/null x265 [info]: HEVC encoder version 3.1.2+1-76650bab70f9 x265 [info]: build info [Linux][GCC 10.1.1][64 bit][noasm] 8bit x265 [info]: using cpu capabilities: none! x265 [info]: Main profile, Level-4 (Main tier) x265 [info]: Thread pool created using 4 threads x265 [info]: Slices : 1 x265 [info]: frame threads / pool features : 2 / wpp(17 rows) x265 [info]: Coding QT: max CU size, min CU size : 64 / 8 x265 [info]: Residual QT: max TU size, max depth : 32 / 1 inter / 1 intra x265 [info]: ME / range / subpel / merge : hex / 57 / 2 / 3 x265 [info]: Keyframe min / max / scenecut / bias: 25 / 250 / 40 / 5.00 x265 [info]: Lookahead / bframes / badapt : 20 / 4 / 2 x265 [info]: b-pyramid / weightp / weightb : 1 / 1 / 0 x265 [info]: References / ref-limit cu / depth : 3 / off / on x265 [info]: AQ: mode / str / qg-size / cu-tree : 2 / 1.0 / 32 / 1 x265 [info]: Rate Control / qCompress : CRF-28.0 / 0.60 x265 [info]: tools: rd=3 psy-rd=2.00 early-skip rskip signhide tmvp b-intra x265 [info]: tools: strong-intra-smoothing lslices=6 deblock sao x265 [info]: frame I: 3, Avg QP:27.57 kb/s: 14018.64 x265 [info]: frame P: 146, Avg QP:28.84 kb/s: 4313.98 x265 [info]: frame B: 451, Avg QP:35.29 kb/s: 204.06 x265 [info]: Weighted P-Frames: Y:0.0% UV:0.0% x265 [info]: consecutive B-frames: 0.7% 0.0% 0.0% 94.6% 4.7% encoded 600 frames in 168.97s (3.55 fps), 1273.22 kb/s, Avg QP:33.68 592.69user 1.89system 2:49.00elapsed 351%CPU (0avgtext+0avgdata 416184maxresident)k 476408inputs+0outputs (1major+95191minor)pagefaults 0swaps So a small improvement.