Core Differences
Forge (2011): most mature, most mods, slower updates (1-3 months for major versions). Fabric (2018): newer, lighter, very fast updates (1 week), better performance with Sodium. Forge dominates large modpacks. Fabric excels in performance and latest version support.
How to Choose
Choose Forge: you want large traditional modpacks (RLCraft, Enigmatica), need specific Forge-only mods, prefer mature ecosystem. Choose Fabric: you want maximum performance (Sodium+Iris), play newest MC versions, light modding, developing your own mod.
Warning: 2025 trend: more classic mods now support Fabric. Create supports both platforms. If unsure, go Fabric — faster, lighter, more modern.