Hi guys, I have the opportunity to update my (very) old MacPro 3.1 to a new iMac with either the i7 (3.8 GHz and 8 cores) or the i9 (3.6 GHz and 10 cores). For photo processing (mainly d810 Nikon raw files) I use darktable (and in some cases Rawtherapee) and GIMP, and for organization I use Digikam (my library contains more than 100000 photos and video files). For video work I use Final Cut Pro. I did try to find information about how the different open source programs may profit from multicore CPU on MacOS, but I did not find anything that was clear to me. I have the feeling that for what I do it will make little difference, if any, but I am a cell biologist!. I think that not to many people in this forum use Macs, but comments, thoughts, recommendations will be highly appreciated and will help me to define my future Mac configuration and, may be, to understand a little better the photo soft I am using. Thank you.
Don’t forget a GPU for opencl acceleration for the likes of Darktable
Hi @zurdo
No, I do not have any Mac statistics/speed data re changing no of cores – but I do have data from when I switched from Ryzen 2700X and GTX-1050 to Ryzen 3900X and GTX-1660 Ti in case that would be enlightening?
Have fun!
Claes in Lund, Sweden
Hi Brian, I forgot to mention the GPU, for the iMac is the Radeon Pro 5700 XT. and I read that Mac is not very supporting of openCL,
Thank you for responding, of couse your experience on this subject will be helpful even if are different systems
@zurdo Here you are:
I used the darktable benchmark test.
- 16 Gig RAM. CPU Ryzen 2700X & GTX-1050 =
7.471 seconds/12.281 seconds (with/without openCL). - 16 Gig RAM. CPU Ryzen 3900X & GTX-1660Ti =
2.925 seconds/12.791 seconds (with/without openCL).
What happens when I change to 32 Gig RAM?
- 2 * 16 Gig RAM sticks =
2.838 seconds/8.396 seconds (with/without openCL). - 4 * 8 Gig RAM sticks =
2.747 seconds/8.366 seconds (with/without openCL).
Note: these clockings were made with git-dev versions of darktable (but not the same version during all tests).
On macOS, OpenCL has been deprecated in favor of Metal. With a newer processor you might be able to run newer macOS which may not support OpenCL. (Apple recommends developers transition from computational OpenCL to Metal/Metal Performance Shaders.)
When replacing mac cpu’s be sure the new chips don’t draw more current than factory. Otherwise they will release the blue smoke. Also, I think you can fit two cpus on the macpro3,1?
If I understand correctly (Claes benchmark tests) and simplifying, going from Ryzen 2700 (8-cores) to Ryzen 3900 (12 cores) does not changes the results (without openCL); but changing the GPU clearly shows an improvement (with openCL).
And from what Hiram mention about MacOS deprecating openCL, any development in darktable to increase performance based on openCL, which I believe is what the developers are doing, will not be profitable running newer macOs with Metal. Thus, at least for darktable any improvement I can expect will be based on cpu frequency. Will see if there are other comments related to GIMP and Digikam. Thank you guys.
Things will change again when Apple Silicon is released. 
Hi Afre, it’s true that things are going to change and I think for the better with the apple chips. Being faithful to Mac since the first Macs, the experience of the transition from powerPc to intel suggests to me that it may not be immediate and I think that programs like darktable, GIMP and Digikam will have to be used with the new Rosetta (with some speed degradation) for several years. The Mac I am using is from 2008, is rather slow when working with the big raw files and also is showing some erratic behaviour at start up, that is why I am thinking in updating to intel while doing very frequent backups!. If there was already a Mac with the expected new Apple chip, the decision, I think would be easier.
Translated with www.DeepL.com/Translator (free version)
hello @zurdo.
I’ve been a faithful follower of the Mac from the beginning. I have a 2010 pro mac flashed in 5.1 bought second hand (westmere 6x3.33Ghz). I turned away from the Apple architecture that I find too closed, but I nevertheless kept my aging pro mac on OsX, which found a real youthfulness as soon as I switched to Linux (manjaro). Under Linux, my mac has found an incredible speed for my use: photo retouching (with Art- nik collection- Digikam) Drawing with Krita, and animation with Blender. Sometimes, without changing hardware, but just OS, you save a few years on your machine ! Anyway, it’s worth a try, it doesn’t cost anything !
Hi J-Luc, thank you for the suggestion and the indo about the soft that can be used under Linux, I was playing with that idea, and looking into linux I was thinking about trying Ubuntu, since I don’t have any experience with Linux, and coming from Mac do you think that manjaro is a better option?
When I started with Linux (coming from Mac) I installed Ubuntu, But I didn’t get hooked with this distribution (just a matter of feeling I think), I then tried Linux Mint (Debian based) which was good, but… not that again !! That’s a bit the advantage and disadvantage of Linux, the choice !!!. I wanted to try a rolling release… arch Linux was tempting me a lot, but the installation difficulty slowed me down, so I installed Manjaro Linux which is also based on Arch, and there, I really loved this distro… At home everything works very well, and it’s the only distro that allows me to run Wine to use some windows software without loss of speed (almost).
But you really have to test it, because what I find good for me, don’t necessarily have it for someone else !
Thank you for sharing your experience, I will read about the alternatives and test.
I’ve got two Imacs both running Linux. The 2010 one which I’m using to type this is running Manjaro KDE and it’s turned a barley usable machine into something which handles the latest photo programs good enough. I’ve been using it mostly for organising with Digikam which it’s powerful enough for, it’s obviously not a speed demon but for a ten year old machine it’s brilliant what it can do now.
My main machine is a 2017 one, I don’t like the way mac os is going and wanted the best performance out of the open source software so decided go back to Linux which I used for years before getting the first mac. I was just using Linux on it up until recently but keep seeing that it’s recommend to have mac os installed on a partition for firmware upgrades, not important for an old machine but thought I better do it on my newer one to avoid any issues. One thing though it gives me something stable so can play around with Linux and don’t have to worry about it if I break it. I’ve currently got Arch installed and trying to get a screen brightness issue solved. I actually missed things breaking when I used mac os, it might sound strange but I learnt a lot from fixing Windows and getting Linux to work over the years. These days though Linux is rock solid stable if you want it to be and mostly hardware just works as it should with it.
Choice is both a good and a bad thing with it there’s bigger differences between desktop environments than the distros but you can make it how you want it pretty much. I use KDE because it’s easier for HiDPI screens than anything else I’ve used. For distros now it’s pretty much just Arch vs Debian the most popular and well supported ones are near enough all based on one of them. Debian great for being rock solid tried and tested and Arch being bleeding edge but still mostly rock solid just more of a chance of breakage and having to problem solve even if using a distro that holds packages back a little.
Hi Nathan, thank you for the comments about Linux/Mac, they are in line with those made in a previous post. I am thinking, as a first step, in going for a dual boot, with an easy to install distro to get some experience with the soft I use (mainly darktable, GIMP and Digikan) in a Linux environment.
Following but not seeing the response that I myself am looking for.
I use both dt and gimp on Mint and I’ve known that dt benefits greatly from a decent GPU, more so than CPU so it appears but I don’t know about gimp.
Is gimp also GPU favoured or CPU favoured?
Based on the GIMP 2.10 release notes GIMP - GIMP 2.10 Release Notes GIMP may benefit from both, multi core CPU and GPU
