Make After Effects render faster: a 12-point checklist

Slow previews are rarely one big problem. They are a stack of small ones: a blur that renders on the CPU, footage the decoder struggles with, a cache on the wrong drive. Go through this list top to bottom. Most projects speed up noticeably after the first five.

1. Give After Effects the memory it deserves

Open Edit › Preferences › Memory & Performance (After Effects › Settings on macOS). Lower RAM reserved for other applications to around 4 GB if nothing else heavy runs alongside. Make sure Enable Multi-Frame Rendering is on; it has been available since the 2022 release and uses every CPU core for previews and exports.

2. Put the disk cache on a fast SSD

In Preferences › Media & Disk Cache, point the cache at your fastest SSD and give it 50 to 100 GB. Rendered frames stay on disk between sessions, so scrubbing a comp you opened yesterday is instant.

3. Preview at half resolution

The resolution menu at the bottom of the Composition panel has nothing to do with the export. Work at Half, switch to Full only to check details. Turn on Adaptive Resolution in the Fast Previews menu (the lightning icon) so scrubbing drops quality instead of dropping frames.

4. Preview only the part you are working on

Press B and N to set the work area to the few seconds you are animating. Use Region of Interest (the dashed rectangle under the viewer) to render only one corner of the frame while you tune a single element.

5. Turn off the three expensive switches while you work

Motion Blur, Depth of Field and Frame Blending are composition switches at the top of the timeline. They multiply render time, and you do not need them while blocking out timing. Turn them on for the final check and the export.

6. Know which effects are slow

Effects with a GPU badge in the Effects & Presets panel render on the graphics card. The rest run on the CPU, and some are famously heavy: Camera Lens Blur, Roughen Edges, CC Particle World, Shatter, and Glow with a large radius. Swap Gaussian Blur (Legacy) for Gaussian Blur or Fast Box Blur. Check that File › Project Settings › Video Rendering and Effects says Mercury GPU Acceleration, not Software Only.

7. Pre-compose and pre-render

A background that does not change from frame to frame should not be re-rendered every time you nudge a title. Pre-compose heavy layers, then use Composition › Pre-render. It sends the comp to the render queue and, when done, replaces it with the rendered file, keeping the original for later changes.

8. Fix the footage, not the comp

H.264 and HEVC from cameras and phones are built for small files, not for scrubbing. Phone clips often have a variable frame rate too, which causes audio drift. Transcode them in Adobe Media Encoder to ProRes 422 LT or DNxHR LB before you import, or right-click the footage in After Effects and choose Create Proxy › Movie. The export still uses the original.

9. Solo, shy and hide

Solo (the dot in the layer switches) the layers you are animating; everything else skips rendering. Shy layers hide clutter from the timeline. Switching off layers you do not currently need, even temporarily, is the quickest speed-up there is.

10. Keep expressions light

Switch the engine to JavaScript in File › Project Settings › Expressions; it is many times faster than the legacy ExtendScript engine. Expressions that call valueAtTime() in a loop across many layers are slow by nature. Once the animation is final, select the property and run Animation › Keyframe Assistant › Convert Expression to Keyframes.

11. Export through Media Encoder

Composition › Add to Adobe Media Encoder Queue (Ctrl+Alt+M) renders in the background while you keep working. Export a ProRes or DNxHR master first, then make the H.264 for upload from that file. It is faster than rendering H.264 straight from the comp, and you can re-encode without re-rendering.

12. Purge when things get weird

If a preview is slower than yesterday for no reason, run Edit › Purge › All Memory & Disk Cache. Before you hand a project over, use File › Dependencies › Remove Unused Footage and Reduce Project so it loads faster for the next person.