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Vulkan conv-direct auto: probe says 'output check failed' on RX 7900 XTX (gfx1100), forced on gives bit-identical images (master-975) #2173
Description
Follow-up to #2134 / #2141. On an RX 7900 XTX the Vulkan conv3d probe of master-975 (95b3090) turns direct convolution off with probe output check failed, but forcing it on gives the same images bit for bit.
RX 7900 XTX (gfx1100, 24 GB), Windows 11, AMD driver's Vulkan, Qwen-Image 2.1 Q4_K, 1152x1536, 30 steps, one LoRA and a reference image, --offload-to-cpu. Same 3 prompts and seeds on each build, release zips.
| build | conv3d direct | VAE decode | total |
|---|---|---|---|
| 3f8527a (older) | not there (vae_conv_direct: false) |
64.8-65.9 s | 290-296 s |
| 1d0a58a | auto: Vulkan0 -> on (implicit GEMM) |
3.7-3.9 s | 218-219 s |
| 95b3090 (master-975), default | auto: Vulkan0 -> off (probe output check failed) |
3.7-4.5 s | 222-227 s |
95b3090, --conv-direct on |
no probe line | 3.6-4.3 s | 222-223 s |
With the probe off, the forced run's PNGs are identical bit for bit to the default run's on all three images, at the same time. So either the probe's output check is too strict on RDNA3 (it fails while the real output is the same), or the forced setting doesn't actually change the path for this VAE. Either way the big VAE gain since 3f8527a is kept on this card, so nothing is lost for Qwen-Image here, but the probe result looks wrong.
Happy to run the probe with more logging if you tell me what to enable.
Activity
wbruna commentedon Oct 20, 2026
Despite the Wan VAE arch itself using both, I believe image generation only uses conv2d; the conv3d probe should probably be skipped in this case.
Check if you get the same results with
--conv-direct on,vae=off.