Lightroom Classic: Interface is very, very slow on iMac Pro

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  • Updated 2 months ago
  • (Edited)
Lightroom Classic CC (latest update atm) interface and other functions are very slow on iMac Pro. The actual edits and file renderings are quick, but interface is lagging, moving zoomed-in photo is very slow. 

Example - scrolling thru folder list on left side is lagging. Scrolling preset list is lagging. Moving photo around with touchpad/touch-mouse is very lagging. 

This is quite shocking to see on iMac Pro, which is supposed to be the super fast computer (and it is in any other respect, except Lightroom). 

Tried with and without GPU acceleration. Didn't notice any difference. 

Display is set to Default resolution.
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Karlis Dambrans

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Posted 9 months ago

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Rick Spaulding, Champion

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Hi Karlis,

Do any of the steps on this page help?
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Karlis Dambrans

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No. I have very few images synced. 
And pre-computation shouldn't be the problem, as the compter is pretty powerfull. 

The problem most likely is some bug or something with interface on retina screen. If i change resolution to lowest - Lightroom speeds up. But then that ruins the whole point of have a large screen. 
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Ryan DeMont

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So I too have a problem with my Imac 4.2ghz '17. The best fix I got, and it's not a complete fix, is to adjust the display resolution. They say that because Mac's have so many pixels, Lightroom can't process images fast enough for them to rendered in real time. Which of course is ridiculous, at least to my non expert Lightroom software building self. It's frustrating because I bought my fast iMac mainly to use with Lightroom and photoshop. But when I adjust my screen resolution I get better results in lightroom. hopefully they'll fix this, but it does seem Mac's with 5k retina display (maybe yours is even more k in the retina's) are left out in lightroom right now
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I have a Mac Pro 2013. Lightroom used to be slow but I got used to it, as long as I had two apple Thunderbolt Displays attached. But when I upgraded to two dell 5k displays, it became RIDICULOUSLY slow. I assume the same is happening with the iMac... it’s so frustrating that j now sync up my pics to the cloud and do at least all the selecting on my iPad. So smooth and nice.. wish it was ever like this on the mac.
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Karlis Dambrans

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This is the setup. Latest OS, latest LR. 

Lightroom Classic version: 7.3.1 [ 1167660 ]License: Creative Cloud
Language setting: en-LV
Operating system: Mac OS 10
Version: 10.13.4 [17E202]
Application architecture: x64
Logical processor count: 16
Processor speed: 3,2 GHz
Built-in memory: 65 536,0 MB
Real memory available to Lightroom: 65 536,0 MB
Real memory used by Lightroom: 6 407,3 MB (9,7%)
Virtual memory used by Lightroom: 12 305,3 MB
Memory cache size: 4 280,8MB
Internal Camera Raw revision: 933
Maximum thread count used by Camera Raw: 5
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 2108MB / 32767MB (6%)
Camera Raw real memory: 2127MB / 65536MB (3%)
Displays: 1) 5120x2880, 2) 1920x1080

Graphics Processor Info: 
Metal: AMD Radeon Pro Vega 56

Application folder: /Applications/Adobe Lightroom Classic CC
Library Path: /Users/fotodelfi/Pictures/Lightroom Catalog/Lightroom Catalog-2.lrcat
Settings Folder: /Users/fotodelfi/Library/Application Support/Adobe/Lightroom

Installed Plugins: 
1) AdobeStock
2) Aperture/iPhoto Importer Plug-in
3) Canon Tether Plugin
4) Facebook
5) Flickr
6) HDR Efex Pro 2
7) Nikon Tether Plugin

Config.lua flags: None

AudioDeviceIOBlockSize: 512
AudioDeviceName: External Headphones
AudioDeviceNumberOfChannels: 2
AudioDeviceSampleRate: 48000
Build: 10.0x7
CoreImage: true
GL_RENDERER: AMD Radeon Pro Vega 56 OpenGL Engine
GL_VENDOR: ATI Technologies Inc.
GL_VERSION: 2.1 ATI-1.66.31
OGLEnabled: true
GL_EXTENSIONS: GL_ARB_color_buffer_float GL_ARB_depth_buffer_float GL_ARB_depth_clamp GL_ARB_depth_texture GL_ARB_draw_buffers GL_ARB_draw_elements_base_vertex GL_ARB_draw_instanced GL_ARB_fragment_program GL_ARB_fragment_program_shadow GL_ARB_fragment_shader GL_ARB_framebuffer_object GL_ARB_framebuffer_sRGB GL_ARB_half_float_pixel GL_ARB_half_float_vertex GL_ARB_imaging GL_ARB_instanced_arrays GL_ARB_multisample GL_ARB_multitexture GL_ARB_occlusion_query GL_ARB_pixel_buffer_object GL_ARB_point_parameters GL_ARB_point_sprite GL_ARB_provoking_vertex GL_ARB_seamless_cube_map GL_ARB_shader_objects GL_ARB_shader_texture_lod GL_ARB_shading_language_100 GL_ARB_shadow GL_ARB_shadow_ambient GL_ARB_sync GL_ARB_texture_border_clamp GL_ARB_texture_compression GL_ARB_texture_compression_rgtc GL_ARB_texture_cube_map GL_ARB_texture_env_add GL_ARB_texture_env_combine GL_ARB_texture_env_crossbar GL_ARB_texture_env_dot3 GL_ARB_texture_float GL_ARB_texture_mirrored_repeat GL_ARB_texture_non_power_of_two GL_ARB_texture_rectangle GL_ARB_texture_rg GL_ARB_transpose_matrix GL_ARB_vertex_array_bgra GL_ARB_vertex_blend GL_ARB_vertex_buffer_object GL_ARB_vertex_program GL_ARB_vertex_shader GL_ARB_window_pos GL_EXT_abgr GL_EXT_bgra GL_EXT_bindable_uniform GL_EXT_blend_color GL_EXT_blend_equation_separate GL_EXT_blend_func_separate GL_EXT_blend_minmax GL_EXT_blend_subtract GL_EXT_clip_volume_hint GL_EXT_debug_label GL_EXT_debug_marker GL_EXT_depth_bounds_test GL_EXT_draw_buffers2 GL_EXT_draw_range_elements GL_EXT_fog_coord GL_EXT_framebuffer_blit GL_EXT_framebuffer_multisample GL_EXT_framebuffer_object GL_EXT_framebuffer_sRGB GL_EXT_geometry_shader4 GL_EXT_gpu_program_parameters GL_EXT_gpu_shader4 GL_EXT_multi_draw_arrays GL_EXT_packed_depth_stencil GL_EXT_packed_float GL_EXT_provoking_vertex GL_EXT_rescale_normal GL_EXT_secondary_color GL_EXT_separate_specular_color GL_EXT_shadow_funcs GL_EXT_stencil_two_side GL_EXT_stencil_wrap GL_EXT_texture_array GL_EXT_texture_compression_dxt1 GL_EXT_texture_compression_s3tc GL_EXT_texture_env_add GL_EXT_texture_filter_anisotropic GL_EXT_texture_integer GL_EXT_texture_lod_bias GL_EXT_texture_mirror_clamp GL_EXT_texture_rectangle GL_EXT_texture_shared_exponent GL_EXT_texture_sRGB GL_EXT_texture_sRGB_decode GL_EXT_timer_query GL_EXT_transform_feedback GL_EXT_vertex_array_bgra GL_APPLE_aux_depth_stencil GL_APPLE_client_storage GL_APPLE_element_array GL_APPLE_fence GL_APPLE_float_pixels GL_APPLE_flush_buffer_range GL_APPLE_flush_render GL_APPLE_object_purgeable GL_APPLE_packed_pixels GL_APPLE_pixel_buffer GL_APPLE_rgb_422 GL_APPLE_row_bytes GL_APPLE_specular_vector GL_APPLE_texture_range GL_APPLE_transform_hint GL_APPLE_vertex_array_object GL_APPLE_vertex_array_range GL_APPLE_vertex_point_size GL_APPLE_vertex_program_evaluators GL_APPLE_ycbcr_422 GL_ATI_blend_equation_separate GL_ATI_blend_weighted_minmax GL_ATI_separate_stencil GL_ATI_texture_compression_3dc GL_ATI_texture_env_combine3 GL_ATI_texture_float GL_ATI_texture_mirror_once GL_IBM_rasterpos_clip GL_NV_blend_square GL_NV_conditional_render GL_NV_depth_clamp GL_NV_fog_distance GL_NV_light_max_exponent GL_NV_texgen_reflection GL_NV_texture_barrier GL_SGI_color_matrix GL_SGIS_generate_mipmap GL_SGIS_texture_edge_clamp GL_SGIS_texture_lod 
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The more I read about this whole topic I’m under the impression that Lightroom for Mac is simply not optimized for amd gpus, and that’s the main problem. I think on a pc with a decent NVIDIA card it should run smoothly, but maybe I’m wrong. What’s obvious to me is that this is not an iMac pro issue, since I have the same problem on my Mac Pro since I attached 5k displays to it. On the adobe support website they elaborate that the GPU support is primarily to cater owners of 4K and 5k displays, and indeed it’s a little bit faster when turned on, but it’s still Painful. Looking at the OSX native photos app for example it’s pretty obvious that with the right optimization it’s well possible to run through thousands of images very smoothly and that this is an adobe issue.
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Karlis Dambrans

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When i move LR window from iMac screen to attached non-retina monitor - everything runs nice and smooth. But on retina screen it's a laggy lag world. 

Of course i could use LR on secondary screen, but that kinda defeats the purpose of the iMac... 
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Victoria Bampton - Lightroom Queen, Champion

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Karlis, have you considered why that might be...? A standard HD screen (1920×1080) is 2 megapixels (MP), whereas your iMac's 5K display (5120x2880) is a whopping 15 MP. This means that Lightroom has to calculate and display nearly 8 times as many pixels on a 5K display, and that takes time and processing power.
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Karlis Dambrans

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I compeletly understand that, but there is still no excuse. Any other app can show, browse and move images arround with no problems. Only LR has performance issues. 
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Exactly! I wanna see how it runs on windows, but have a hunch that it will be a very different experience. The same like with after effects. What I find crazy is how amazing the performance is on iOS- maybe they could bring over some of these improvements to the Mac?
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Harvey Kaufmann

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I am having the same issues in LR Classic 7.x on a iMac Retina 5k and I've also been trouble-shooting for months with little improvement. My best solution has been to rollback to LR 7.2 Classic and off-load any serious editing to other programs.

While I understand the resolution on the iMac 5k Retina requires significantly more processing (compared to HD screen resolution) it is not a problem for Photoshop CC  2018 or several other programs (Affinity, Luminar & OnOne) when editing the same files. I'm also not a technician but I presume (possibly incorrectly) that the graphics card on the iMac has the muscle to help out on all these calculations if it is utilised efficiently. Clearly, some developers have managed to do this.

So I'm left wondering if the resolution is THE ISSUE, then why is the latest version of such a great program as Lightroom Classic not meeting specs that these other programs seem to be able to manage? My iMac is a late model with an SSD and 32GB of fast ram - right now I'd be happy with middling performance but I'm not even getting that.

AND I also note that my iPad displays and edits all of the images I'm struggling with on the iMac with absolute ease.

I really love (and need!) LR Classic but it's not usable at this time.
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Julian Manuszewski

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At this point, I'm so used to trouble shooting LR that nothing really surprises me, but I've got one that will really make everyone chuckle today.  For the most part, LR Classic 7.4 now runs smoothly on my MacBook Pro laptop... but is almost unusable on my absurdly priced 10 core, 128GB RAM, 3.1 GHz, Radeon Pro Vega 64 stacked iMac Pro.  I understand the limitations of the software and it's lack of multicore application, but this is frankly absurd.

The issue is this: graphics acceleration in LR is still in beta, but without it LR can't keep up with displays over 4k in resolution.  I'm glad the graphics acceleration crop bug was fixed with the recent update, but currently my options are as follows...

1. Edit on my 16GB RAM laptop with no issues.

2. Edit on the 5k iMac Pro display with graphics acceleration turned ON.  This renders the used of the adjustment brush, cloning, healing, and any local adjustments completely broken.  Initial brush strokes cause the entire system to choke for 2-3 seconds and are often not even recorded.  I edit hundreds of images a day and each of them receives a pass with a few healing spots and adjustments so this is a very big issue for me.

3.  Edit on the 5k iMac Pro display with graphics acceleration turned OFF.  This fixes the adjustment brush issue, but makes regular develop functions extremely sluggish and bloated.  Moving around within lightroom is also slow.


What gives?  I'm tired of being used as a beta tester.  If this program is built for professionals, it should run perfectly on an $8,000 machine and especially on a high resolution display.


iMac Pro

3.1 GHz Intel Xeon W

128 GB 2666 MHz DDR4

Radeon Pro Vega 64 16368 MB

5k Retina Display

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Karlis Dambrans

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Item afraid they just don’t care about the “classic” app anymore and soon will force everyone to use the new CC app.
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Julian Manuszewski

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Will this ever be addressed?  Still seeing absurd lag on screens above 4k.  Months later and nothing has changed.... 

Thanks Adobe 

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Stijn Algoet

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Same here, lightroom sucks on the new imac, yet overall this machine is a killer 
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Sergiu Salcau

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just got the 5K 2017 iMac and lightroom stutters when i scroll and now i see that bridge has issues too. what the hell. i mean seriously, does adobe expect us to pay for the membership and not be able to use it properly. i didn t have any scrolling stutter on my old 2012 !!!!!! Retina macbook pro and i have on the 2017 iMac. are you shitting me adobe ? this is unacceptable. DO SOMETHING.