Dual 3090 AI Workload Causes System Hard Lockup
fgoricha · reddit · 2026-07-18
The author is troubleshooting a dual RTX 3090 rig: both cards run extended AI tasks perfectly fine individually, but under combined load, the entire machine hard-locks after a few hours. Monitors lose signal, the network drops, fans and LEDs keep spinning, and a hard reboot is required.
Known details:
- Motherboard: EVGA X299 FTW K, CPU: i9-7940X, RAM: 128GB, PSU: 1600W.
- Both 3090s are in dedicated x16 PCIe slots with a one-slot gap between them.
- The issue occurs at both 100% and 80% power limits, with temps and power draw appearing normal before the crash.
The author is seeking next diagnostic steps, highlighting broader stability issues with multi-GPU local training/inference.
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