Head-to-Head Spec Duel · /pc
RTX 3090 24GB vs RTX 4080 Super 16GB — Local LLM & Chassis Clearance Duel
Which GPU wins for running 32B quantized LLMs locally vs 4K ray-traced gaming inside a mid-tower ATX case?
96
NVIDIA GeForce RTX 3090 24GB
24GB GDDR6X (936 GB/s) • 304mm Length • 350W TDP • Runs 32B Q4_K_M @ 42 tok/s
Est. Street/MSRP ~$799
VS
88
ASUS ProArt RTX 4080 Super 16GB
16GB GDDR6X (736 GB/s) • 300mm SFF-Ready • 320W TDP • Runs 14B Q4_K_M
Est. Street/MSRP ~$999
| Technical Specification Metric | NVIDIA GeForce RTX 3090 24GB | ASUS ProArt RTX 4080 Super 16GB | Real-World Fitment Impact | Verdict |
|---|---|---|---|---|
| VRAM Pool for Local LLMs | 24 GB GDDR6X (936 GB/s) | 16 GB GDDR6X (736 GB/s) | 32B Q4_K_M requires 19.8GB VRAM; 16GB offloads to system RAM (5× slower) | +8GB VRAM on RTX 3090 |
| Chassis Length Clearance (Lancool 216 392mm) | 304 mm (+88mm margin) | 300 mm (+92mm margin) | Both clear Lancool 216 (392mm) and Fractal North (355mm) without removing front fans | Both 100% Fit ✓ |
| ATX 3.1 1.3× Transient PSU Load (with 7800X3D) | 676W Peak (on 850W PSU) | 637W Peak (on 850W PSU) | Corsair RM850e ATX 3.1 retains +174W to +213W safe headroom on both cards | 850W ATX 3.1 Locked ✓ |
| Est. Street Price / MSRP | ~$799 (Street / Renewed) | ~$999 (Retail MSRP) | Saves ~$200 while gaining +8GB VRAM for AI workloads | -$200 Street Advantage |