Enhanced video and audio playback: After Effects CC 2015.3 (13.8) uses a new playback architecture to deliver real-time playback of cached frames with synced audio. The new architecture is shared with other Adobe applications, like Premiere Pro and Audition.
Effect rendering on the GPU: The Lumetri Color, Gaussian Blur, and Sharpen effects can now render using your computer’s GPU. This improves rendering performance for these effects by 2x-4x over rendering using only the CPU (depending on the frame being rendered and the speed of your GPU). GPU effect rendering is controlled via the new Video Rendering and Effects option in the Project Settings dialog.
Performance improvements: Many small changes under the hood include faster import and caching of image sequences, asynchronous drawing of viewer panels, faster opening of large projects, improved expression caching, and more.
Additional native format support: Apple ProRes QuickTime files can be decoded on Windows without needing QuickTime installed on the system. RED camera raw file decoding now supports RED Scarlet-W, Raven, and Weapon cameras, including 8K .r3d footage.
Lumetri Color effect improvements: The Lumetri Color effect can now render using your computer’s GPU, and includes new HSL Secondary controls and new SpeedLooks presets.
And even more: Many additional small improvements, such as a Swap Colors button in the Tint effect, refinements to project auto-save, and many bug fixes.