AI Denoise never completes on Intel Arc 140T (Core Ultra) — GPU at 100% compute, progress stuck — worked in ~1–2 min on earlier LrC versions — LrC 15.4.1 + Intel 32.0.101.8860

AI Denoise consistently fails to complete on my machine. This is 100% reproducible and has persisted across multiple Lightroom Classic and Intel driver versions, including the current pairing of both.

System:

• Lightroom Classic 15.4.1 [202606201310-b9f148a4], Camera Raw 18.4
• Windows 11 Home 26200
• Intel Core Ultra laptop, 16 logical cores, 32 GB RAM
• Intel Arc 140T integrated GPU (16 GB shared), driver 32.0.101.8860 WHQL (current, verified in Device Manager)
• Files: Fujifilm RAF (X-Trans)

Symptom:

1. Click Denoise. The background progress indicator (top-left) immediately shows roughly 10% progress, then never advances — waited well over an hour.
2. The photo becomes locked: "AI processing is in progress for this photo. Editing is temporarily unavailable."
3. Task Manager shows the Arc 140T near 100% compute utilisation for the entire time, so the GPU is actively executing something — it just never finishes.
4. Exiting Lightroom during this state leaves orphaned Lightroom processes that must be killed in Task Manager.
5. This is a regression. On earlier LrC versions (a couple of months ago, modal Denoise dialog era), Denoise on this same machine with the same type of RAF files completed in roughly 1–2 minutes when it ran. It was already unstable and frustrating to use - it would regularly freeze mid-run, requiring Lightroom to be killed in Task Manager, and typically took a few attempts per photo - but successful runs at least completed in minutes. So the Arc 140T is demonstrably capable of executing this workload in minutes. In the current version (and possibly the one immediately before it), Denoise never completes at all: the GPU computes at 100% indefinitely.

Diagnostics already done:

• Windows System event log (filtered Critical/Error/Warning): no Display/TDR events, no Event 4101, nothing GPU-related during Denoise runs.
• Reliability Monitor: no LiveKernelEvent 141, no hardware errors on test days.
• So this is not a driver crash/reset loop — the GPU computes indefinitely without completing. This matches Intel community reports of Denoise on Arc taking 12–92 minutes per photo (e.g. Arc A310 thread).
• Mains power, Windows "Best performance" power mode: no change.
• Tried with Preferences > Performance > Use Graphics Processor set to Auto, and then also to Custom with "Use GPU for image processing" unticked, and also Off: no change - as documented elsewhere, Denoise ignores this preference and uses the GPU regardless. There is currently no supported way to run Denoise on CPU, and DisableGPUInference.txt explicitly does not cover Denoise per the ACR GPU FAQ.
• Timed test (7 Aug 2026): Denoise started on a single RAF at ~21:05. As of 23:00+ it had still not completed — over 1 hour 50 minutes on one photo, progress indicator unmoved from its initial position throughout. So far I have not had a denoise complete, it appears to be processing, but without progress, maybe even in an infinite loop, can’t tell. 
• GPU utilisation logged with typeperf (60-second samples, one full hour): the Arc 140T's Compute engine sat at 95–100% in every single sample, attributable to one process (Lightroom), with zero dips, pauses, or resets - the GPU is continuously executing without ever finishing. Log CSV available on request.
• CPU comparison test (Arc disabled in Device Manager, forcing CPU denoise) to follow in a comment.

Related reports:

• Intel community, Arc 140T + LrC GPU-intensive tasks (escalated to Adobe Jan 2026): https://community.intel.com/t5/Graphics/Issue-using-Arc140T-with-Adobe-Lightroom-Classic-with-intensive/td-p/1731291
• Intel community, Arc Denoise extreme slowness: https://community.intel.com/t5/Intel-ARC-Graphics/ARC-Lightroom-Denoise-issues-any-updates-coming/td-p/1679272

Requests:

1. Please investigate what changed in the Denoise/AI inference path in recent LrC / Camera Raw releases with respect to Intel Arc. Since earlier versions completed in 1–2 minutes on this exact hardware and the current version never completes, this looks like a software regression rather than a hardware capability limit. I am paying a monthly fee, and expect this to work on what is standard and powerful hardware. There was never any indication on purchase that intel Arc is not supported. 
2. Please coordinate with Intel on the Arc inference path — Intel has publicly stated this requires joint work between the companies.
3. Please provide a supported option to run Denoise on CPU. On this hardware the CPU would complete in minutes; the GPU never completes, and there is no user-accessible fallback short of disabling the GPU in Device Manager.

Full LrC System Info available on request, but I think you’ll agree I’ve provided detailed info above, so please investigate as a priority.