RimWorld’s new engine promises faster colonies without a fresh start

RimWorld is testing a replacement for the engine beneath its colonies. Update 1.7 moves the game from Unity to Ludeon's own Waylith engine, with the studio reporting faster simulation and loading. The public test is on Steam's unstable branch; the main branch remains on 1.6 in the announcement.

The most consequential promise is continuity. Ludeon says saves can move between 1.6 and 1.7, while most mods should continue working without changes. For players whose investment is a colony built over many evenings, an engine upgrade is much more attractive if it does not require abandoning that history.

The studio's October 12 post gives concrete examples: a late-game colony ran 2.2 times faster in its stress test, and a 1,500-mod setup loaded in six minutes instead of fourteen. Those are developer measurements on particular workloads. They are not a guarantee that every PC, colony or mod collection will improve by the same amount.

Simulation speed is not just frame rate

RimWorld has at least two kinds of performance that a player can notice. One is how frequently the screen updates. Another is how quickly the simulation processes the work of colonists, animals and the surrounding world. A game can draw a smooth image while its accelerated simulation struggles to advance as quickly as requested.

That is why Ludeon's reference to ticks per second matters. A tick is a simulation step, rather than necessarily a newly displayed frame. Improving that work can help a large colony feel more responsive even when a screenshot looks unchanged. Loading speed addresses a different interruption: how long a player waits before reaching the colony at all.

PC Gamer's coverage includes encouraging player reports alongside a warning about memory use. Those reports are useful early observations, but their different hardware and mod lists prevent a controlled comparison. A faster load on one machine does not establish a lower memory requirement on another.

Compatibility is the demanding part

Replacing an engine without changing the visible game is an unusual kind of upgrade: success can look like nothing happened, except that waiting takes less time. It requires the surrounding systems to keep interpreting existing content as players expect.

Mods make that promise harder. Some alter data; others depend on code behavior or assumptions about the runtime. Even when most work unchanged, the remaining exceptions may include the particular combination a player considers essential. A broad compatibility statement should therefore guide expectations without replacing a check of the actual mod collection.

Ludeon asks mod authors to test their work and mark compatible releases for 1.7. It also warns that PCs more than ten years old may not run the new version. The message is a reminder that optimization for one class of machines can coexist with a changed compatibility floor.

Try the branch without losing the baseline

The studio documents the route through Steam's game Properties and Betas menu, where the branch is named unstable. Keeping a separate copy of a valued save and recording the current mod list provides a baseline for comparison. A backward-compatible file format is helpful, but it is not a substitute for preserving the exact setup that produced a working colony.

GeekRadar's earlier coverage of Enshrouded's save-migration problems illustrates why continuity deserves attention alongside performance. The games face different technical changes; the shared player concern is whether hours of progress survive them.

For PC gaming, Waylith's significance is the possibility of improving a mature simulation without resetting its community's work. The beta's job is to establish how broadly that promise holds beyond the studio's own test colonies.