Used RTX 3090 Buying Guide for Local LLM in 2026

Cross-posted from Best GPU for LLM — visit the original for our VRAM calculator, GPU comparison table, and current Amazon pricing. The RTX 3090 is three generations old, costs under $900 used, and still fits 34B models that a new $500 GPU cannot touch. For LLM inference, VRAM is the hard constraint — and 24GB at ~$850 is the best value on the market in 2026. But the used GPU market has landmines: mining-worn cards, dead VRAM chips, and sellers who know you can't easily tell the difference befo...