P: (MacOS26) Photoshop v27.5 & later extremely high GPU usage from the WindowServer process
I have several M1 Macs—from Mac mini to iMac—and they all have the same issue. Whenever I open Photoshop, Illustrator, or InDesign, even if I don’t do anything, WindowServer will jump to around 80–90% GPU usage. Once I start working with files, even just opening a single image, the whole system becomes choppy and starts dropping frames, with GPU usage almost maxed out.
But : if I switch the app to full-screen with menu bar mode (press F), the window shadows disappear, GPU usage drops back to normal, and everything runs smoothly—even with large files open. This makes it pretty clear the issue is related to how window shadows are being handled in macOS 26 and how it interacts with Adobe apps.
It’s been months since Adobe 26 came out, and I’ve been waiting for updates to fix this, but even the latest versions still haven’t solved it. At this point, I’m wondering if it’s even fixable.
M1 Macs are not that old—most Mac minis and iMacs from around 2021–2022 are still M1, so they’re definitely not outdated. It shouldn’t be the case that running basic Photoshop functions causes this level of lag. Mac and Adobe are supposed to be a perfect combination.
Even though macOS 26 seems to put more load on the GPU, Apple’s own apps don’t have this issue at all. For example, Final Cut Pro runs large projects smoothly without any problems like this caused by window shadows.
I really hope this gets fixed. Or is it just impossible to solve, meaning the only options are either upgrading to the newest Mac or back to macOS Sequoia?...
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