If you’re a designer or photographer, you’ve probably heard of GIMP — the image manipulation software that has been a free alternative to Adobe Photoshop for a long time. It’s hard not to be a fan of GIMP. Since 1995, it has become one of the largest open-source projects for raster graphics editing. When you don’t need all the bells and whistles of professional software, GIMP is a perfect fit — until you encounter its slow performance.

Why is GIMP slow on Mac?

Being a free, open-source project, GIMP doesn’t have processes in place that other software companies do — from code reviews and QA testing to support team day-to-day operations. GIMP also needs to work well on multiple operating systems, including macOS, Windows, and Linux. Therefore, software updates can often cripple GIMP performance and make it slow. 

I’ve seen these issues come up in open-source projects first-hand. Thankfully, the community is usually just as good at helping you as they are at building the software. So let’s get started with ways to speed up GIMP.

1. Disable OpenCL Hardware Acceleration

Sometimes, you may take the slow performance of your Mac for GIMP’s lags. So, before you start searching for a reason why GIMP slows down your device, give your Mac a good push first. I recommend using an Apple-notarized software, CleanMyMac X. Just install the tool, open it, and click the Scan button. It checks your Mac for unneeded files and removes system junk to help your Mac run faster.

If you notice that adjusting curves and rotating images takes longer than expected, you might be able to resolve the issue in your graphics processing settings. GIMP has seen some issues in the past with Nvidia and Intel graphics drivers, which have interfered with GIMP’s OpenCL Hardware Acceleration. So it might be better to disable it:

  1. Open GIMP.
  2. Navigate to Settings from the menu bar.
  3. Click System Resources.
  4. Find Hardware Acceleration and deselect “Use OpenCL.”

Now, check if it worked. Try performing the same action before and after disabling OpenCL. If you see no difference, go back and re-enable OpenCL, as it may boost performance in other processes. 

2. Try a different color profile

Most designers try to calibrate their monitor’s color profile to their working conditions and then request their software to match that profile. But sometimes, the algorithms behind these color profiles can hit snags in GIMP’s own code or interfere with your macOS native profiling. To fix this:

  1. Open GIMP.
  2. Navigate to Settings.
  3. Click Color Management.
  4. Under Monitor Profile, deselect “Try to use the system monitor profile.”

From here, you can run a quick test on GIMP to see if performance has improved. If so, you may want to go back into your Color Management settings to select one of the existing software profiles from the dropdown menu. Pick the one that matches your monitor.

3. Reinstall GIMP altogether

It’s hard to collaborate on open-source software, especially when development support is at the mercy of its contributors. That means bugs and issues can slip past the software updates or your files can be fragmented after installing new updates on top of existing ones. There’s a process for raising bugs with the community, but in the middle of rendering your work, the last thing you feel like doing is writing a support ticket. To reinstall:

  1. Head to the GIMP website.
  2. Click the Download link.
  3. Select the latest macOS package.
  4. Drag the files into your Applications folder.

The fresh install shouldn’t have any interference with older version files, and you can get back to work knowing you’re running the latest solid build. 

4. Free up some RAM to cure slow GIMP

Overcoming some of GIMP’s potential issues and weak points is a good place to start, but what if it’s still sluggish? Since GIMP’s performance is directly related to the available RAM, you can decrease the amount of RAM used by applications on your Mac. My personal favorite is a space optimizer, CleanMyMac X. For those who are curious to check it out, here’s how it works:

  1. Download a free edition of CleanMyMac X.
  2. Go to Maintenance under the Speed tab.
  3. Select Free Up RAM (and any other applicable ones).
  4. Click Run.

CleanMyMac X is the best utility app for running all sorts of optimizations, including shaping up your RAM use, clearing user and system caches, and analyzing your disk space. Now, check back with GIMP to see how much faster it has become. Repeat the CleanMyMac X scan once in a while and you’ll be able to speed up GIMP on-demand anytime.