RimWorld 1.7 Moves to Ludeon’s Waylith Engine, With 2-4x Faster Performance

RimWorld 1.7 is available now on Steam’s unstable beta branch, moving the colony sim from Unity to the Waylith Engine, Ludeon Studios’ first in-house engine. The team says performance is “improved by 2-4x” in its tests, with a late-game colony benchmark of 2.2x faster than 1.6 and a 1500-mod modpack load time cut from 14 minutes to 6 minutes.

The main branch stays on 1.6 for now. Players can opt in to the beta by right-clicking RimWorld in their Steam library, opening Properties, and choosing the “unstable” branch under Betas. You can track the move to the main branch on our release calendar.

Compared to 1.6, Ludeon says 1.7 is faster at startup, map generation, world generation, ticks-per-second, and “just about everything else,” especially with big mod lists. The studio tuned Waylith around a colony of 40 colonists, 200 ducks, and 100+ mods, and that scale is now expected to run much smoother. Ludeon cautions that real-world gains will vary by PC and mod list, and that 1.7 may not run at all on hardware more than 10 years old.

Savegames and most mods carry over. 1.6 saves load on 1.7, and 1.7 saves work on 1.6. The vast majority of mods work without changes, though some will show a yellow “potentially unsupported” warning until authors mark them as 1.7-compatible. Modders also get the latest C# features, easier paths to complex mods, and better support for big visual effects, with less performance hit. Ludeon thanked “over two dozen modders” who tested 1.7 ahead of the public beta.

In a short “One more thing” at the bottom of the post, Ludeon confirmed that RimWorld isn’t the only Waylith project. “RimWorld isn’t the only game on Waylith. We’re working on something new!” the studio wrote, without naming it, sharing a genre, or giving a release window. It is a similar pattern to studios such as Konami planning multiple new Silent Hill games – one engine, more than one product in the pipeline.

Our read: Engine migrations rarely end as a clean win, but this one is: the same game, faster, with a more capable modding layer built in. For a concrete Ludeon-supplied case, the 1,500-mod modpack the studio used to stress-test Waylith dropped from a 14-minute load to a 6-minute load. The same 1.7 build hit 2.2x on a long-running late-game colony. Those are the studio’s own numbers, not a marketing claim, and they map directly onto the heavy-mod players who would feel the change most. The new-game tease is thin, but the engine is the bigger story for anyone who plays or mods RimWorld. If you have a heavy mod list or a 1.6 colony you don’t want to abandon, 1.7 on the beta is worth a test this week. The same applies if you’re following another long-running indie in active development like Hytale.

Edited by Kerwin Stewart, Editor-in-Chief · How we report