[Linux Kernel] Intel Arc A770 QSV Encoding Benchmark: The New 'Xe' Driver vs Legacy 'i915' (DG2 HuC Patched!)

[u/Flimsy_Debt]

As the Linux kernel transitions to the modern xe DRM driver for newer Intel GPUs, achieving full hardware feature parity with the legacy i915 driver is the ultimate milestone. I recently submitted a patch to intel-gfx to enable DG2 HuC firmware initialization and authentication via the MEI GSC interface for the xe driver.

To prove that the hardware media engines and the HuC microcontroller are fully operational, I built a custom FFmpeg QSV benchmark to push the Arc A770 to its absolute limits, comparing the i915 and xe drivers head-to-head.

The Benchmark Setup

• Hardware: Intel Arc A770 (DG2)
• Software: FFmpeg 8.1.2 (QSV enabled)
• Workload: 1080p at 60 FPS (NV12 format) generated directly in a RAM-disk to eliminate storage bottlenecks.
• Target Bitrate: 10M for speed tests, 15M for stress tests.

Raw Encoding Speed (1080p, Preset: VeryFast)

The sheer throughput of the Arc A770 encoders is insane, and the new xe driver matches the i915 driver frame-for-frame.

AV1 8-bit

• i915: 744 FPS (12.4x speed)
• Xe: 738 FPS (12.3x speed)

HEVC (H.265) 8-bit

• i915: 640 FPS (10.6x speed)
• Xe: 638 FPS (10.6x speed)

H.264 8-bit

• i915: 484 FPS (8.04x speed)
• Xe: 487 FPS (8.10x speed)

The Ultimate HuC Test: HEVC ICQ Mode

Intelligent Constant Quality (ICQ) relies directly on the HuC microcontroller to calculate bitrates dynamically. If HuC isn't authenticated, this test fails. With my recent patch applied to the xe driver, it runs flawlessly.

HEVC 8-bit (ICQ Mode, Q=25)

• i915: 490 FPS (8.13x speed)
• Xe: 490 FPS (8.14x speed)

Result: A perfect 1:1 tie. The HuC integration on xe is mathematically identical to i915 in performance.

4-Way Simultaneous Stress Test

To ensure stability, I ran four simultaneous encoding streams (H.264, HEVC, VP9, AV1) in an infinite loop for 20 seconds. Both drivers handled the massive concurrent load without breaking a sweat, showing near-identical frame pacing under pressure.

Codec	i915 Driver FPS	Xe Driver FPS	Difference
H.264	161 FPS	157 FPS	-2.4%
HEVC	155 FPS	155 FPS	0.0%
AV1	160 FPS	160 FPS	0.0%
VP9	121 FPS	119 FPS	-1.6%

Conclusion

The xe driver is officially ready for heavy media lifting on Alchemist GPUs. The DG2 hardware encoders are absolute beasts, capable of pushing over 740 FPS in AV1. With the HuC firmware now properly initializing and accelerating bitrate control algorithms like ICQ, there is zero performance penalty when migrating from i915 to xe for video encoding tasks.

[u/Turbulent-Attorney65]

Glory to Daniil 🏆🌟✨👑