Prime noise reduction = sluggish UI

Running Win 7 and quad core hyperthreaded I7 processor. When prime NR is selected for any images the UI gets intermittently sluggish with jerky mouse movements.

Multithreading and priority of prime NR is messed up. Annoyingly PL2 wastes CPU and gives a jerky UI while processing the prime NR preview even when the noise reduction tab is closed and the preview is not visible.

When you say selected, are you talking about selecting PRIME while you are editing, or when you’re exporting? Just selecting when editing doesn’t seem to have any obvious affect on my Windows 10 i7 machine with 24 gb of ram, an SSD drive and a older, middle of the road, NVidia GTX 745. Perhaps a mlld flutter for a second or so, if even that much. Exporting a 30-35 MB raw image to a full resolution Jpeg with PRIME NR selected takes between 27-35 seconds depending on file size, and I don’t do any editing while exporting.

I’m not surprised that the tab being closed and the preview not being visible makes any difference as all since the bulk of PRIME processing is probably done in the background.


Yonni, the only solution I’ve come up with is to only enable Prime Noise Reduction as a last stage. You can select all your export photos and then add/adjust Prime on all of them and it immediately applies the same reduction. For re-editing I’d use the same method to disable prime. I understand the relationship between Prime Noise Reduction and my 5DS R files and know that depending on ISO/light somewhere between 12 and 20 is perfect. Applying as a group is no issue in terms of adjustment (if I wonder, I’ll do a single file first).

Fast Noise Reduction is pretty powerful in its own right. Not sure it previews much faster but you could experiment with switching noise reduction systems just before export.

DxO has a lot of serious work to do in terms of preview speed and interface fluidity with larger files. Two pieces of advice:

  • implement proxies partly based on size (only process the parts of the image which are needed when at 100%; process image fit views at screen resolution (or double, just not the whole 8688x5792 pixel image): this is an issue for 8K screens of course. Very few of us have or particularly want them (I’m on 4K happily).
  • use GPU acceleration on the proxy files

This would give us instant real time: C1 has fully responsive slider adjustment and it makes me cross that DxO PhotoLab doesn’t it.

For the same reason that Adobe had to drop GPU processing for export in Adobe Premiere, GPU acceleration is not suited for export (not accurate enough). It’s the lack of fluidity while editing that drives me batty not the waiting on export so it wouldn’t bother me at all to have two slightly different pipelines.

But I’m sure DxO know that already. Why they don’t hire someone with those skills and ask him to build just those parts of the pipeline is a bit of a mystery to me.

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[quote=“uncoy, post:3, topic:7656”]
Yonni, the only solution I’ve come up with is to only enable Prime Noise Reduction as a last stage.[/quote]

I am pleased to hear it isn’t just me although it seems not everyone. I also sometimes leave prime NR selection till just before export, however, it is a pain and I generally only use prime on higher ISO shots from a mixed set so it is easier to choose while making other adjustments.

Not wasting CPU generating previews that may never be viewed would be an improvement regardless.

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