Home / Compare / NVIDIA RTX 5090 32 GB vs NVIDIA RTX 4090 24 GB
NVIDIA RTX 5090 32 GB vs NVIDIA RTX 4090 24 GB for local AI
Canonical GPU chips, not ASUS vs MSI coolers. Memory fit uses calculator v1.0.0. Speed uses published llama.cpp estimates only. Query states (model / quant / context) are not indexed.
Decision dimensions
These are facts from the existing memory calculator, performance cache, and Amazon summary. This page does not pick a winner.
| NVIDIA RTX 5090 32 GB | NVIDIA RTX 4090 24 GB | |
|---|---|---|
| Advertised VRAM | 32 GB | 24 GB |
| Usable VRAM (calculator 90%) | 28.8 GB | 21.6 GB |
| Architecture | Blackwell | Ada Lovelace |
| Memory | GDDR7 · 1792 GB/s · 512-bit | GDDR6X · 1008 GB/s · 384-bit |
| Models fully fitting at Q4 / 8K | 47 | 41 |
| Limited context / offload / does not fit | 0 / 7 / 1 | 0 / 12 / 2 |
| llama.cpp short-context coverage | available | available |
| Mapped / Amazon-matched SKUs | 8 / 8 | 17 / 11 |
| Lowest fresh matched Amazon card | $4799.99 Check price | $2579.99 Check price |
| Current price per advertised VRAM GB | $150 / GB | $107 / GB |
Prices are the lowest fresh Amazon-matched board-partner SKU in the last 24 hours, not MSRP. Price per GB is that price divided by advertised VRAM — not a value score.
Difference in those current lowest fresh cards: +$2220.00 (+86%).
Workload
Runtime is llama.cpp CUDA — the only runtime with published Phase 5 estimates. Changing the model does not create a new indexable URL.
What each GPU uniquely fits
Full VRAM fit at Q4 / 8K among published calculation-supported models. Identical coverage is reported as such — it is not turned into a winner.
Fits fully only on NVIDIA RTX 5090 32 GB (6)
Fits fully only on NVIDIA RTX 4090 24 GB (0)
None
41 models fit fully on both · examples: Gemma 2 27B Instruct, Mistral Small 24B Instruct, GPT-OSS 20B, StarCoder2 15B, Qwen3 14B, DeepSeek R1 Distill Qwen 14B, Phi-4, Qwen2.5 14B Instruct.
llama.cpp performance
Reuses Performance Model v1.0.0 published rows only. Short-context llama-bench pp512/tg128. Not 8K–128K speed. Methodology
Select a model to load published decode estimates for the same workload on both GPUs.
What this comparison shows
- Memory capacity: NVIDIA RTX 5090 32 GB has 8 GB more advertised VRAM.
- Model fit: at Q4 / 8K, NVIDIA RTX 5090 32 GB fully fits 6 additional supported models.
- Performance: No published llama.cpp performance estimate for either GPU.
- Current commerce: lowest fresh matched NVIDIA RTX 5090 32 GB SKU $4799.99; NVIDIA RTX 4090 24 GB $2579.99.
Board power / TDP is not compared: RigForAI does not yet have a single normalized watt metric. Energy per token is out of scope. This is not a best-GPU ranking.