I'm playing a heavily modded Minecraft setup on Windows 11 with an RX 9070 XT, Ryzen 7 7800X3D, and 32 GB of RAM. Every few minutes, my frame rate suddenly falls from around 150 FPS to roughly 30 for a few seconds, then returns to normal. During the stutters, GPU usage also drops from nearly 100% to about 50%. Could the CPU be bottlenecking the game, since Minecraft relies heavily on a single core? I've tried different memory allocations, and assigning 7–8 GB seems to work best, so I'm not sure RAM is the problem. The setup includes Cobblemon, Distant Horizons, animation and texture packs, plus several optimization mods. What should I check to find the cause?
4 Answers
Minecraft isn’t literally limited to one core, but its main game thread is often the performance limit. If that thread is busy, the GPU can show reduced utilization because it is waiting for new work. Compare frametimes and individual CPU-core usage during a stutter, and test with Distant Horizons, shaders, resource packs, and large world-generation features disabled one at a time.
Eight gigabytes allocated to Minecraft should generally be enough, and assigning more memory can sometimes make garbage-collection pauses worse rather than better. One problematic mod could also be causing a long tick, an error loop, or repeated chunk processing. Check the game log and profiler, then temporarily remove groups of mods to narrow down which one causes the spikes. Chunk-generation mods and distant-view systems are especially worth testing separately.
A short GPU usage drop usually means the GPU is waiting on something else, such as chunk generation, world data loading, garbage collection, or a mod taking too long to complete. It may be worth checking whether the game is installed on a slow or unhealthy drive, and monitoring CPU core usage, disk activity, temperatures, frametimes, and memory usage while the stutter occurs.
Those components shouldn’t normally bottleneck each other. Check CPU usage per core rather than only looking at total CPU usage, because Minecraft can max out one thread while overall CPU usage appears fairly low. Shaders, Distant Horizons, and a large modpack can also cause periodic world-generation or rendering spikes. Minecraft’s Java/OpenGL performance can be inconsistent even on powerful hardware.
I was mainly wondering about a CPU limit because Minecraft relies so much on one core. The pack includes Cobblemon, Distant Horizons, animation and texture packs, and optimization mods such as C2ME, FerriteCore, ModernFix, More Culling, ImmediatelyFast, and others, so it may simply be pushing one part of the game too hard.