RUNLOCALAIv38
→WILL IT RUNBEST GPUCOMPARETROUBLESHOOTSTARTPULSEMODELSHARDWARETOOLSBENCH
RUNLOCALAI

Operator-grade instrument for local-AI hardware intelligence. Hand-written verdicts. Real benchmarks. Reproducible commands.

OP·Fredoline Eruo
DIR
  • Models
  • Hardware
  • Tools
  • Benchmarks
  • Will it run?
GUIDES
  • Best GPU
  • Best laptop
  • Best Mac
  • Best used GPU
  • Best budget GPU
  • Best GPU for Ollama
  • Best GPU for SD
  • AI PC build $2K
  • CUDA vs ROCm
  • 16 vs 24 GB
  • Compare hardware
  • Custom compare
REF
  • Systems
  • Ecosystem maps
  • Pillar guides
  • Methodology
  • Glossary
  • Errors KB
  • Troubleshooting
  • Resources
  • Public API
EDITOR
  • About
  • About the author
  • Changelog
  • Latest
  • Updates
  • Submit benchmark
  • Send feedback
  • Trust
  • Editorial policy
  • How we make money
  • Contact
LEGAL
  • Privacy
  • Terms
  • Sitemap
MAIL · MONTHLY DIGEST
Get monthly local AI changes
Monthly recap. No spam.
DISCLOSURE

Some links on this site are affiliate links (Amazon Associates and other first-class retailers). When you buy through them, we earn a small commission at no extra cost to you. Affiliate links do not influence our verdicts — there are cards we rate highly that we don't have affiliate relationships with, and cards that sell well that we refuse to recommend. Read more →

SYS · ONLINEUPTIME · 100%2026 · operator-owned
RUNLOCALAI · v38
  1. >
  2. Home
  3. /Compare
  4. /Hardware
  5. /Custom
Custom comparison✓Editorial·Reviewed May 2026

NVIDIA GeForce RTX 5090 vs NVIDIA GeForce RTX 4090

Spec-driven comparison from our catalog. For curated editorial verdicts on the most-asked pairs, see the head-to-head index.

Editorial verdict available: We have a hand-written buyer guide for this exact pair. Read the editorial verdict →

Pick your two cards

▼ CHECK CURRENT PRICE
Check on Amazon →
Affiliate disclosure: we earn a small commission on purchases made through these links. The opinion comes first.
▼ CHECK CURRENT PRICE
Check on Amazon →
Affiliate disclosure: we earn a small commission on purchases made through these links. The opinion comes first.

Spec matrix

DimensionNVIDIA GeForce RTX 5090NVIDIA GeForce RTX 4090
VRAM
32 GB
flagship (FP16 32B / quantized 70B+)
24 GB
high (70B Q4 comfortable)
Memory bandwidth
1792 GB/s
excellent (>1.5 TB/s)
1008 GB/s
strong (800 GB/s - 1.5 TB/s)
FP16 compute
125 TFLOPS
82.6 TFLOPS
FP8 compute
250 TFLOPS
—
Power draw
575 W
extreme (1000W+ PSU)
450 W
extreme (1000W+ PSU)
Price
~$2,499 (street)
~$1,899 (street)
Release year
2025
2022
Vendor
nvidia
nvidia
Runtime support
CUDA, Vulkan
CUDA, Vulkan

Spec data from our hardware catalog. This is a generated spec compare, not a hand-written editorial verdict. For editorial picks on the most-asked pairs, see our curated head-to-heads.

Most users should buy

Primary recommendation

NVIDIA GeForce RTX 5090

32 GB usable VRAM unlocks flagship (FP16 32B / quantized 70B+) workloads that the NVIDIA GeForce RTX 4090's 24 GB ceiling can't reach. For most local AI buyers in 2026, VRAM ceiling is the dimension that matters most.

Decision rules

Choose NVIDIA GeForce RTX 5090 if
  • You target flagship (FP16 32B / quantized 70B+) workloads — 32 GB is the working ceiling for that.
  • You hate used silicon and want a warranty. The NVIDIA GeForce RTX 5090 is the new-with-warranty alternative.
Choose NVIDIA GeForce RTX 4090 if
  • You're comfortable with used silicon and prioritize $/GB-VRAM.

Biggest buyer mistake on this comparison

Buying based on the spec sheet without verifying the actual workload requirement. Run /will-it-run with your specific model + context-length combination before committing — the math is exact and frequently surprising.

Workload fit

How each card handles common local AI workloads. “Tie” means both cards meet the bar; pick on other axes (price, ecosystem, form factor).

WorkloadWinnerNotes
Coding agents (Aider, Cursor, Continue)TieCode agents work fine on 16 GB for 13-32B models. 24 GB unlocks 70B-class code models (DeepSeek Coder V3, Qwen 2.5 Coder).
Ollama / LM Studio chatTieBoth run Ollama fine. 16 GB unlocks multi-model serving via OLLAMA_KEEP_ALIVE.
Image generation (SDXL, Flux Dev)NVIDIA GeForce RTX 5090Image gen is compute-bound. 24 GB VRAM unlocks Flux Dev FP16 + LoRA training. Below 24 GB, Flux Dev FP8 only with offloading.
Local RAG (embedding + LLM)TieRAG with 70B LLM concurrent fits at 24 GB. Embedding model overhead is negligible (<1 GB).
Long-context chat (32K+ context)Tie32 GB unlocks 32K+ context on 70B Q4 comfortably.
Voice / Whisper transcriptionTieWhisper Large V3 fits in 4-8 GB. Both cards likely overkill for transcription-only workloads.
Video generation (LTX-Video, Mochi)TieLocal video gen production-ready at 32 GB.
Multi-GPU tensor parallel (vLLM, ExLlamaV2)NVIDIA GeForce RTX 4090Tensor-parallel scaling works on PCIe 4.0 x8/x16. Used cards typically win on $/GB-VRAM at scale (dual 3090 vs single 5090).

VRAM reality check

  • Multi-GPU does NOT pool VRAM by default. Two 24 GB cards = 48 GB combined ONLY when the runtime supports tensor-parallel inference (vLLM, ExLlamaV2, llama.cpp split-mode). For models that don't tensor-parallel cleanly, you're stuck at single-card VRAM.
  • At 32 GB+, FP16 32B inference works comfortably. 70B Q4 with 32K+ context fits. Multi-model serving (parallel KV cache headroom) becomes practical.

Power, noise, and thermals

  • NVIDIA GeForce RTX 5090 TDP: 575W. NVIDIA GeForce RTX 4090 TDP: 450W. Plan PSU sizing for transient spikes — sustained AI inference draws closer to nameplate TDP than gaming benchmarks suggest. Add 200-250W headroom over GPU TDP for the rest of the system.
  • Used cards: replace thermal pads on any used purchase older than 18 months ($30-50 + 1 hour of work). Ex-mining cards specifically — cooler reseat improves thermals 5-10°C, often the difference between throttling and stable load.

Used-market intelligence

  • Mining-rig provenance is dominant for used NVIDIA GeForce RTX 4090 listings. Not inherently disqualifying — mining wears fans (replaceable) and thermal pads (replaceable), rarely silicon. Verify ECC error counts with nvidia-smi (or vendor equivalent); any value above ~100 = walk away.
  • Demand a 30-minute under-load demonstration before paying — screen-recorded inference at 90%+ utilization. Sellers refusing this are red flags.
  • Replace thermal pads on any used GPU older than 18 months. Cheap insurance ($30-50 + 1 hour) that often delivers 5-10°C cooler operation under sustained inference.
  • Used cards have no warranty. Budget for a 2-3 year operational horizon and plan to resell if your usage tier changes. Used silicon resale is mature in 2026 — selling later is realistic.

Upgrade-path logic

  • NVIDIA GeForce RTX 4090 → NVIDIA GeForce RTX 5090 is a real VRAM-tier upgrade (24 GB → 32 GB). Worth it if you're outgrowing the lower-tier ceiling on 70B-class workloads.

Better alternatives to consider

Lower power alternative
Apple Mac mini M4 Pro — silent low-power alternative →

Both cards in your comparison draw 350W+. If power budget matters, M4 Pro Mac mini delivers 48 GB unified memory at ~75W full system.

Quick takes

NVIDIA GeForce RTX 5090

Blackwell flagship. 32GB GDDR7 on a 512-bit bus delivers ~1.79 TB/s memory bandwidth — the new top of consumer hardware for local LLM inference. Comfortably loads 70B Q4 with room for context.

Full verdict →

NVIDIA GeForce RTX 4090

The community-default high-end local-AI card from 2022 to 2025. 24GB GDDR6X at ~1 TB/s makes 70B Q4 comfortably loadable.

Full verdict →

Related buyer guides

  • Best GPU for local AI →
  • Will it run on my hardware? →
  • CUDA out of memory — when VRAM is the limit →

Where next?

Curated head-to-heads
OrBest GPU for local AIAll hardware verdicts
Buyer guides
  • Best GPU for local AI →
  • Best laptop for local AI →
  • Best Mac for local AI →
  • Best used GPU for local AI →
  • Will it run on my hardware? →
Compare hardware
  • Curated head-to-heads →
  • Custom comparison tool →
  • RTX 4090 vs RTX 5090 →
  • RTX 3090 vs RTX 4090 →
Troubleshooting
  • CUDA out of memory →
  • Ollama running slowly →
  • ROCm not detected →
  • Model keeps crashing →
Specialized buyer guides
  • GPU for ComfyUI (image-gen) →
  • GPU for KoboldCpp (RP/long-context) →
  • GPU for AI agents →
  • GPU for local OCR →
  • GPU for voice cloning →
  • Upgrade from RTX 3060 →
  • Beginner setup →
  • AI PC for students →
Updated 2026 roundup
  • Best free local AI tools (2026) →