Unreal Engine Crashing Using DX12 / Flickering / Melting Viewport when Opening external Windows

After weeks of Unreal Engine 5.6 behaving like my GPU was melting every time I opened an external window (Material Editor, Blueprint, Niagara, etc.), I finally figured out what’s causing it — and more importantly, how to fix it.

This post is for anyone running a 4070 / 4080 / 4090 (Ada GPUs) and dealing with:

  • Screen flickering

  • “Melting” viewport

  • Freeze for a few seconds

  • EXCEPTION_ACCESS_VIOLATION

  • Crashes when opening asset editors

  • DX12 instability

Switching to DX11 only hides the problem. It doesn’t fix anything, and you lose ray tracing + path tracing.

Why This Happens

I’m on:

  • NVIDIA 4070 Ti Super

  • Windows 11

  • NVIDIA Driver 581.57

  • Unreal Engine 5.6

This combination is broken by default.

  • UE5.6 uses an updated DX12 pipeline + Agility SDK

  • The 581.xx branch of NVIDIA drivers is tuned for AI workloads

  • 581.xx is unstable for DX12

  • The new UE5.6 Editor Viewport changes trigger crashes on Ada GPUs

So if you’re using 581.57, it’s not your GPU, not your PSU, not overheating —

it’s the driver + UE 5.6 misbehaving.

THE FIX

Downgrade your NVIDIA driver to any of these stable versions:

:check_mark:552.22 — Stable (recommended)

:check_mark:551.76 — Very stable

:check_mark:546.33 — Safe fallback

:warning: Do NOT use anything from the 58x branch.

Every 581.xx driver I tested caused DX12 instability in UE5.6.

I personally switched to 552.22 and Unreal is working perfectly again —

DX12, ray tracing, path tracing, everything.

Results After Downgrading

  • No more “melting” viewport

  • No flickering

  • No freeze when opening Material Editor

  • No EXCEPTION_ACCESS_VIOLATION

  • DX12 stable again

  • Ray tracing + path tracing fully functioning

UE 5.6 returns to normal.

Why I’m Posting This

I saw a lot of people fighting the same issue and wasting days thinking it’s:

  • a bad GPU

  • a PSU problem

  • Windows reinstall time

  • Unreal bug

  • overheating

  • plugins

  • shader cache

  • corrupted project

No.

It’s simply UE 5.6 + 58x NVIDIA drivers = disaster.

If you downgrade to 552.22 or 551.76, the problem disappears instantly.

Hope this saves someone the hell I went through.