Slow screen re-draw - Color Efex Pro on M1 Macbook

When I use Nik Color Efex pro and cycle through my favorite recipes, I find the screen has a block-like redraw that is slow. It also makes it difficult to compare the recipe effects. Not sure if anyone has seen this and/or can offer a fix (video of it below with views of Activity Monitor for RAM/CPU during).

2021 M1 Pro MacBook Pro with 16gb RAM running Ventura and using Nik Color Efex 4. The MacBook Pro is feeding a 27" Eizo CS2740 and a 25" Dell Ultrasharp UP2516D. The RAM is low - just couldn’t wait for a BTO 32gb model at the time I purchased. It is possible that is the issue given the shared ram but figured would see if there might be other answers/fixes.

This has been a problem for a while but never realized there was a DxO forum to post to.

Hi, Eyal.

I’m running a Mac mini M1 with 8GB memory, on Ventura, with two 27-inch Asus monitors and have never seen this problem. I’m at version 5.4 but had version 4 previously; didn’t happen then either.

There is a setting in Color Efex Pro to toggle GPU use on or off; does that make any difference?

Does it happen on both monitors? If you run Color Efex with only one monitor connected, does it still happen? Probably that doesn’t help solve the problem, but if there is a change, it might mean something.

I looked through the release notes for each of the version 5 releases and while your specific issue isn’t described, there are several fixes related to interaction with displays that may make a difference. You might try contacting DxO support directly (there is a link at the bottom of the page to see if they think upgrading could be a solution.

Sorry I couldn’t offer more!


You are absolutely correct Dale.

I did a few experiments and it does seem to be an issue related to the number of displays and resolution of them.

With the MacBook display on and the Eizo only plugged in, Nik works perfectly.

With the MacBook, Eizo and Dell, I’m okay as long as the Eizo resolution is kept to 2560; anything higher and I get the block writing.

Looks like the 16gb of shared memory is not enough to run 2 larger externals.


Ah, that’s great. Glad to hear my post helped you find a workaround. Not ideal, I suppose; but at least when you’re using Color Efex you have a way to give your eyes a break!


Hi Eyal,
Maybe your issue is due to the “mac’s dirty secret” :wink:
The way macOS handles the UI scaling is unique and very different from what you have on Windows.
In the past I had issues with my mac: working on my 28" 4K monitor was very slow…until I found out why.

First of all, the memory is shared between the GPU and the computer…so at the end 16GB may be very liitle, considering that an entry-level GPU has (nowadays) at least 8GB of memory…

Then there is the biggest issue: if you run your monitor at a screen resolution which is not native or half the native resolution, macOS will double the resolution you have chosen than scale it back to the right size.
Example: if I’m running my 28" 4K monitor at a scaled resolution of 3008x1692 (easier on my eyes on a 28") macOS will, in reality, upscale the resolution to 6016x3384, then resize the image to 3008x1692.

As you can see, working on 4K monitor in this case will stress the GPU like if I were using a 6K display!!!
BTW, in the preferences, when you choose a scaled resolution, the little grey text says “this may affect performance”. LOL.
And if you are feeding 2 external monitor, you can see how quickly the way macs handle the UI scaling is the real bottleneck…


Yup - that was exactly the reason and that is my preferred resolution.

The tiny sentence really should be in 50pt bold font for the effect it has.

Interestingly, I only hit the limits of the setup when having LR and PS and running Nik so not actually that bad for a 16gb shared memory system but now I know what to look for in the future m3 variant.

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