How to Allocate RAM Correctly for the Distant Horizons + Iris Modpack

Why RAM Matters Here

Distant Horizons stores LOD data for huge areas, and shaders add their own memory overhead. Too little RAM causes crashes and stutter; too much can also hurt performance because of how Java handles garbage collection.

Choosing Your Allocation

Open your launcher's Java settings and find the memory or RAM allocation option. The modpack lists guidance: a very low amount will crash, a minimum amount works with slight stutter at modest render distances, and the recommended amount is the sweet spot for typical play. Going far above the recommendation can sometimes be counterproductive.

Match your allocation to your render distance. If you keep LOD render distance modest, you can stay near the minimum. If you push render distance high, move toward the recommended amount.

Applying and Verifying

Save the setting and launch the game. Open the debug screen (F3) and check the memory readout. If memory usage sits near the maximum constantly, you may need more. If it stays low, you may have allocated too much.

Avoid running other memory-heavy programs alongside the game. If crashes persist after adjusting RAM, lower Distant Horizons render distance before adding more memory.