How to Speed Up Your Mac for Photo Editing

You import 600 RAW files from a wedding shoot, hit the develop module in Lightroom, and the first slider drag takes four seconds to register. Photoshop opens a 2GB layered PSD and spinner-locks for thirty seconds. The Mac isn’t broken — it’s choking on scratch disk space, an 80GB Lightroom catalog with previews, and Adobe’s background helpers. Here’s how to fix all of that in about fifteen minutes.

RAM and the scratch disk problem

Photoshop and Lightroom both use a “scratch disk” — temporary file space they spill to when RAM runs out. By default, both use your startup disk. If your internal SSD is nearly full, scratch operations crawl, and editing speed tanks.

Two rules:

1. Keep at least 20% of your startup disk free, more if your projects are large
2. Make sure RAM isn’t already maxed out before launching Adobe apps

Open Activity Monitor’s Memory tab. Memory Pressure should be solid green. If it’s yellow or red before you’ve even opened Photoshop, you’re going to have a bad time.

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Clear Adobe’s leftover scratch and cache

Adobe apps leave a remarkable amount of debris behind, especially after crashes or force-quits. Some of the worst offenders:

• ~/Library/Application Support/Adobe/Common/Media Cache Files/
• ~/Library/Application Support/Adobe/Common/Media Cache/
• ~/Library/Caches/Adobe/
• ~/Library/Caches/com.adobe.Photoshop/
• ~/Library/Caches/Adobe Camera Raw/Cache2/

The Camera Raw cache alone can hit 50+ GB on a working machine. You can change its size in Photoshop or Bridge under Camera Raw Preferences > Performance > Maximum Size.

Sweep picks up all of these automatically and tells you exactly what’s safe to delete before you click. If you’d rather do it manually, quit Photoshop and Lightroom first — deleting cache while Adobe apps are running can corrupt them.

Tune Photoshop’s memory and history

Photoshop’s RAM allocation is set conservatively by default. Bump it up:

1. Photoshop > Settings > Performance
2. Under Memory Usage, drag Photoshop to use 70-80% of available RAM if you have 16GB+, or 60% if you’re on 8GB
3. Set History States to 20 (the default 50 is overkill and eats RAM)
4. Set Cache Levels to 4 for lots of small/medium files, 6 for fewer huge files
5. Add a second scratch disk (an external SSD) if your internal drive is tight on space

Restart Photoshop for the changes to take effect.

Lightroom catalog hygiene

Lightroom catalogs accumulate cruft over years. The catalog itself is a SQLite database, plus there are previews, smart previews, and 1:1 previews that can balloon to hundreds of gigabytes.

Slim it down:

1. Optimize the catalog: File > Optimize Catalog. Compacts the database. Run this monthly if you import heavily.
2. Delete 1:1 previews you don’t need: Library menu > Previews > Discard 1:1 Previews. They auto-regenerate when needed.
3. Trim the catalog backups: Lightroom keeps every backup forever. Look in ~/Pictures/Lightroom/Lightroom Catalog/Backups/ and delete anything older than three months.
4. Move the catalog to fast storage: catalogs on slow drives are painful. SSD only.

Move libraries off the startup disk if it’s full

If your internal SSD is at 90%+ capacity, Photoshop and Lightroom will both feel sluggish regardless of RAM. Options:

• Move Lightroom catalog and previews to an external Thunderbolt SSD
• Keep originals on a NAS or external drive, working previews local
• Archive old catalogs you don’t actively use

On Apple Silicon Macs with 256GB or 512GB SSDs, this is the single most common cause of slow Lightroom that no one talks about.

Quit Adobe’s background helpers

Even when Photoshop and Lightroom aren’t running, Adobe Creative Cloud spawns a small army of background processes: Adobe Desktop Service, CCXProcess, Core Sync, Adobe Crash Reporter, and the genuinely-named node process running Adobe’s helper.

Quit them when you’re not using Adobe apps:

1. Open Activity Monitor, search “Adobe”
2. Force-quit anything not part of an active Adobe app
3. To stop them launching at login: System Settings > General > Login Items > Open at Login, remove Adobe Creative Cloud

Sweep’s app uninstaller can fully remove the Adobe Creative Cloud helper if you don’t actually use the manager itself, only the apps.

Free up GPU memory for big files

Photoshop uses the GPU for canvas rendering, brush strokes, and many filters. Lightroom uses it for develop module previews. Both share the same unified memory pool on Apple Silicon, so freeing system RAM also frees GPU resources.

Before opening a large composite or starting a heavy edit:

1. Quit browsers, Slack, Discord
2. Run Sweep’s speed boost
3. Confirm Memory Pressure is green
4. Open the Adobe app

Activity Monitor’s GPU history (Window menu > GPU History) shows you exactly how loaded the GPU is — useful for spotting when a background process is silently using GPU cycles.

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Disable Photos.app analysis

If you use Apple Photos as well as Lightroom, the Photos.app library runs face recognition, scene analysis, and “memories” generation in the background — sometimes for days after a big import. This silently steals CPU and disk I/O from your editing apps.

Pause it:

• Apple menu > System Settings > General > Login Items, find anything Photos-related
• Or close the Photos app entirely while editing in Lightroom

Update macOS, Photoshop, and Lightroom

Adobe ships meaningful Apple Silicon performance improvements in nearly every monthly update. macOS does the same with Metal. Old versions of Photoshop on a new Mac will absolutely feel slower than current ones.

• Apple menu > System Settings > General > Software Update
• Adobe Creative Cloud > Updates tab

If you’ve been holding back from Sonoma or Sequoia “in case something breaks”, check Adobe’s compatibility page first — the major Adobe apps are usually safe within a month or two of a macOS release.

A pre-edit checklist

Before a long photo session:

1. Quit browsers, sync clients, Mail, Photos
2. Sweep one-click cleanup (cache, RAM, runaway processes)
3. Verify 20%+ free disk space on the scratch disk
4. Confirm Lightroom catalog is on SSD (internal or Thunderbolt)
5. Open Photoshop, check Settings > Performance shows healthy RAM allocation
6. Begin editing

For most photographers, this routine reclaims 30-50% of editing speed without spending a dollar on hardware. The Mac was always capable — it just needed someone to clear the runway.