'm trying to diagnose severe microstuttering in Rust and I'm looking for people with similar hardware/behavior.
Specs:
- Ryzen 7 9800X3D
- RTX 5060 Ti 16GB
- 32GB DDR5-6000
- Samsung 990 Pro NVMe
- MSI B650 Gaming Plus WiFi
- Windows 11
- 240Hz monitor
The weird part is that average FPS is not the problem. I can be around 180-220+ FPS while the game feels extremely choppy due to frametime spikes.
The issue scales heavily with server population / players:
- Low-pop vanilla servers are dramatically smoother.
- High-pop official servers (~500 players) can feel terrible.
- More players/active player workload seems to make it worse.
- GPU usage can have plenty of headroom when the stutters happen.
I've done CapFrameX captures and the large frametime spikes line up almost entirely with CPU Active, not GPU Active. During one large hitch, for example, frametime was ~23.6ms, CPU Active ~21.7ms, while GPU Active was only ~3ms.
I also captured the issue with Windows Performance Analyzer. Rust has a very heavily loaded Unity/Rust thread, while total CPU usage isn't particularly high. Because Unity/Rust symbols aren't available, I can't identify the exact function responsible.
The most interesting test so far: disabling SMT in BIOS made the game noticeably smoother on the same high-pop server.
It didn't completely eliminate the CPU-side frametime spikes, but the difference in actual gameplay was significant. This makes me wonder if Rust's player/entity workload is interacting badly with SMT/thread scheduling on my system.
I've already ruled out a lot of basic stuff:
- CPU temperatures/clocks are normal
- CPU/RAM stress testing is stable
- GPU isn't maxed during many of the stutters
- Changing graphics settings doesn't solve it
- GC collection didn't solve it
- Player culling settings can affect it but don't fix it
- G-SYNC/V-Sync isn't the root cause
Another important detail: after a completely clean Windows installation, Rust initially ran perfectly smoothly on this exact PC. After a later hard system freeze/reboot, the severe stuttering returned.
I'm not claiming this proves a Rust/Unity bug or an SMT bug. I'm trying to figure out why player-heavy Rust workloads produce such bad CPU-side frametime spikes on this system.
Anyone with a 7800X3D / 9800X3D / other X3D CPU seeing the same high-pop vs low-pop behavior?
I'd especially be interested if someone can compare Rust with SMT enabled vs disabled and capture frametimes with CapFrameX.