GPUFits
GPU Comparisons for Local LLMs
Each comparison page includes a build-time computed spec table, a side-by-side verdict matrix with theoretical speed for 14 mainstream models at Q4_K_M @8K, bandwidth/VRAM-per-dollar value metrics, plus hand-written analysis and FAQs. Verdicts and speeds are formula estimates, not measurements.
| Comparison | VRAM (usable) | One-line verdict |
|---|---|---|
| RTX 3090 vs RTX 4090 | 24.0 GB vs 24.0 GB | For pure LLM inference, buy the 3090: same 24GB, an identical verdict matrix, bandwidth only 8% behind, at less than half the 4090's used price. The 4090 buys convenience, efficiency, and gaming. |
| RTX 4090 vs RTX 5090 | 24.0 GB vs 32.0 GB | If you can buy at MSRP, take the 5090: the 32B tier moves from tight to comfortable and decode is 78% faster. At street prices neither card is rational — the 4090 carries a discontinuation premium, the 5090 trades at ~2× MSRP. |
| RTX 4070 Ti Super vs RTX 3090 | 16.0 GB vs 24.0 GB | LLM-first: take the 3090 — 24GB vs 16GB is the qualitative line between 'runs 24-32B' and 'cannot'. Choose the 4070 Ti Super only if gaming comes first or you have zero mining-risk tolerance. |
| RTX 3060 12GB vs RTX 4070 Ti Super | 12.0 GB vs 16.0 GB | Under $300 targeting the 8B tier: RTX 3060 12GB. Need Phi-4 14B / gpt-oss-20b: pay up for the 4070 Ti Super. For 24B+, neither card works. |
| RTX 3090 vs RX 7900 XTX | 24.0 GB vs 24.0 GB | Linux + willing to tinker: RX 7900 XTX — half the price, same 24GB, slightly more bandwidth. Want CUDA ecosystem certainty and a multi-GPU path: RTX 3090. |
| RTX A6000 vs RTX 3090 | 48.0 GB vs 24.0 GB | For 70B on one card: RTX A6000 (48GB, fits at the ceiling). If you accept dual-card tinkering: two 3090s — same capacity, double the aggregate bandwidth, ~$600 cheaper. |
| Mac Studio M3 Ultra (96GB) vs RTX A6000 | 72.0 GB vs 48.0 GB | Need 60-72GB capacity with zero ops: Mac Studio M3 Ultra. Want the CUDA ecosystem at half the price: RTX A6000 — but its 48GB stops at a ceiling-tight 70B Q4. |
| Mac mini M4 Pro (48GB) vs RTX 3090 | 36.0 GB vs 24.0 GB | Silent, plug-and-play, targeting ≤32B: Mac mini. Want speed, the CUDA ecosystem, and an upgrade path (dual-card 70B): a used RTX 3090 build. |
Data verified 2026-09-01