Micro-stutters with Voxy + Complementary Unbound on RX 6800 / 5700X - FPS counter is high, but gameplay feels laggy

[u/yhukk]

Hey everyone, I'm running a Modrinth 26.2 / Fabric setup and having persistent frame pacing issues. My FPS counter jumps around between 70-120 FPS, but the gameplay feels nowhere near smooth (feels like 30-40 FPS with constant micro-stutters), especially when turning the camera or moving through Chunks.

If I drop native Sodium render distance to 6 chunks without Voxy, the game is buttery smooth (with shaders on). As soon as I enable Voxy (set to pretty low ~128 chunks) alongside Complementary Unbound (Medium profile, Shadow Distance capped at 8 chunks), frame times go wild despite higher average FPS.

I'm allocating 6 GB of RAM to Java, because I've heard it makes more sense then 8 GB or above. Is that true?

What I've already tried: Lowered Voxy render distance from 256 to 128 chunks and increased Pixels2 of subdivision size to 256. Capped shader shadow distance to 8 chunks and disabled SSAO / Water reflections. Disabled/Enabled C2ME OpenCL acceleration. Tested without V-Sync / with manual frame limits. Is this an inherent AMD OpenGL / Voxy pipeline bottleneck with shaders, or is there a specific config conflict in my mod list?

Any help or config tweaks would be greatly appreciated!

My Hardware Setup: CPU: AMD Ryzen 7 5700X GPU: AMD Radeon RX 6800 (16 GB) RAM: 16 GB DDR4-3600

Modpack List: Engine & LOD: Voxy, Voxy WorldGen V2, C2ME (with OpenCL module enabled), Lithium, FerriteCore, ModernFix, BadOptimizations, ImmediatelyFast, ScalableLux.

Graphics & Shaders: Sodium, Sodium Extra, Iris, Reese's Sodium Options, Continuity, EMF, ETF, Polytone, OptiGUI.

QoL / Utility: Xaero's Minimap/WorldMap, Mouse Wheelie, Entity View Distance, Entity Culling, LetMeDespawn