[Help] Massive FPS drops (1–10 FPS) in endgame, 9950x3d / RTX 5080

Hey Exiles,
I’m running into a weird issue where Path of Exile drops from 240+ FPS down to 1–10 FPS whenever there’s a lot of monsters on screen. Elsewhere, everything is buttery smooth.

So far:
*Reinstalled CPU + GPU drivers
*Set CPU/GPU power profiles to maximum performance
*Set Shader Cache to unlimited
*Enabled NVIDIA Smooth Motion
*Unassigned CPU #0 from PoE process
*Set PoE process priority to High
*Linked shader roaming directory → actual game directory (mklink /J)
*Switched RAM from EXPO1 (6000MHz) to EXPO2 (5600MHz) for stability
*Made sure virtual cores 16–31 are parked
*Ran Steam file verification multiple times
*Tried all renderers (DX11, DX12, Vulkan)
*Tried different upscalers (DLSS, XeSS, FSR) and toggled various graphics options
Tried playing on the lowest possible settings


Issue:
*FPS stays around 240 normally
*Drops to 1–10 FPS when huge monster packs appear
*Happens on any renderer or settings combo
*Feels like a CPU/shader stall rather than a GPU bottleneck

System specs:
*GPU: MSI GeForce RTX 5080 Ventus 3X OC Plus — 16 GB GDDR7 (DLSS 4)
*Motherboard: MSI MAG X870 TOMAHAWK WIFI
*CPU: AMD Ryzen 9 9950X3D — 16 cores / 32 threads, AM5 socket, 170 W TDP
*Memory: Patriot Viper Venom DDR5 — 64 GB (2×32 GB) @ 6000 MHz CL30 (PVV564G600C30K)
*Cooling: Arctic Freezer III Pro 360 mm Liquid Cooler
*PSU: Corsair RM1000x (2024 Edition) — 1000 W 80+ Gold
*Storage: Samsung SSD 990 Pro

What else can i try ? Please, i want to play this game a bit more before my vacation ends ;_; .

What exactly do u consider "lots of monsters on the screen"?

Is it just opening a Breach in a T16 map, fully juiced T17 with delirium or something in between?

PoE has always had issues with too many monsters on the screen, particularly in blight maps. At some point the game just stops working because it can't process all the calculations anymore.

That shouldn't happen in normal scenarios with ur system tho, that's why u need to be a little bit more specific. I mean u're basically running the best CPU on the market, but even with that u will run into CPU bottlenecks in PoE with the right amount of monsters.