Why is PL2 so slow?

On some sliders it takes unto 8 seconds for results to show.
Could it be that my computer is at the bottom of the minimum requirements?
iMac (Retina 5K, 27-inch, Late 2015)
3.2 GHz Intel Core i5
32 GB 1867 MHz DDR3
AMD Radeon R9 M380 2048 MB


I am not an expert on this but I do not think so. I have an imac late 2012, 16 RAM. And is is quite fast.
Have you contacted support already?

My specs are:

iMac, Late 2012, 27 inch
2,9 GHz, Intel Core i5
NVIDIA GeForce GTX 660M 512 MB

Not yet…

I have an iMac mid-2011, 27" w/ high end specs. PhotoLab adjustments are near instant for me.

My images are 12-20 MB (Raw).

The differences may be in the processor and graphics card.

Indeed. I have a Core i7 3.4 GHz; AMD Radeon HD 6970M 1024 MB; 16 gigs of RAM.

The Corei7 is definitely a step up. The GPUs are pretty close. You have more RAM.
Much higher res screen.

I believe RAM & CPU are the largest influencers with PhotoLab for manipulation of an on screen image.

Still, whatever the ultimate balance of the hardware’s affect, I would not have expected a 1 second vs 8 second differential (assuming image pixel count is similar).

With a 5K 27 inches screen, you may be often over 75% of zoom with your image.

In that case, DPL is working at full detail resolution (except Prime), and this may take long, depending of your image size.


Same machine here, but with 24 Gigs of RAM.

The performance issue that bugs me most is documented here:

Plus: Boring lag between pushing a slider and visibility of the effect. Lr Classic CC is snappier!


I have tried several of these RAW converters and they all have their individual issues running on my Mac.
Seems like the only solution is to buy a new computer with maxed out specs just to run the software.:wink:
I tried Exposure V4 and it was essentially unusable. After some correspondence with support they said that their software will simply not work on a 5K iMac.

I do like PL2.
Interesting though, that I never have issues with Photoshop, Affinity etc.

I haven’t opened Lightroom 6 in quite a while.
Just now did a test.
All sliders show immediate results when shifted back and forth quickly.


…there is more to speed than sheer power…

PL2 barely uses my GPU at all.
For zooms and pans yes, but for everything else it only uses the CPU.
It’s not using the GPU power for filters, noise reduction, exports etc.

NX-D uses GPU far more.
Affinity Photo do to.
Darktable is as bad on GPU acceleration as PL2 but they push the CPUs even harder.

PhotoLab have soo much that is superior to everything but the sheer speed.
If only they would give us proper GPU acceleration.


I went through this a year ago. Turns out I had too many images in the folder (flat folder containing 2500 images). I created folders for years and then months - opening PL was markedly quicker. I think it had something to do with indexing.


I do not see why an iMac should have speed issues with PL. I run it on a MacBook Pro, which is not nearly as fast as an iMac, and I have no performance issues. Changes show up almost immediately when I use the sliders so I wonder what might be the issue with an iMac.

Of course I do have 32GB of RAM and am working with an internal ssd so perhaps you might have a hardware issue?

It’s not every slider that’s slow.

Which ones are slow?

Same issue. I found that PL2 is very slow with indexing and gets worse with more and more pictures.

I opted to use FastRawViewer for cataloguing and browsing and forget about using PL2 for that.


The exposure and selective tone sliders are slower than contrast.
They are slowest at 100% view, taking about 4 seconds to update.
Faster at “fit” updating in about 2 seconds.

On1 is slightly faster with the same photo.


I am just now testing FastRawViewer.
One nice feature of FRV is it can be set to also delete .dop and .on1 sidecar files when rejecting a photo that had been adjusted in both applications.


I had tested FRV some time ago but decided to not use it. Perhaps it needs another look.