RTX 4090 vs RTX 5090: Specs, VRAM & Price
Short answer: pick the RTX 5090 when you're VRAM-constrained: larger batches, bigger context windows, or models that don't quite fit in 24GB. Pick the RTX 4090 when your workload already fits comfortably in 24GB and you'd rather bank the price difference.
The RTX 4090 has 24 GB of VRAM; the RTX 5090 has 32 GB.
You can rent both by the hour, no purchase required. RTX 4090 from $0.416/GPU/hr; RTX 5090 from $0.642/GPU/hr. The RTX 4090 is 35% cheaper at the entry rate.
RTX 4090
Good for inference and light fine-tuning workloads
RTX 5090
Good for inference and light fine-tuning workloads
Last updated: 2026-11-03 UTCRefreshes every 6 hours
Specs side by side
| Spec | RTX 4090 | RTX 5090 |
|---|---|---|
| VRAM | 24 GB | 32 GB |
| Memory bandwidth | 1,008 GB/s | 1,792 GB/s |
| Architecture | Ada Lovelace | Blackwell |
| Compute capability | 8.9 | 12.0 |
| Precisions in hardware | FP32, FP16, BF16, FP8, INT4 | FP32, FP16, BF16, FP8, INT4 |
| Max board power (TDP) | 450W | 575W |
| Form factor | PCIe 4.0 x16 | PCIe 5.0 x16 |
| Regions | 3 | 3 |
On-demand price
| Rate | RTX 4090 | RTX 5090 |
|---|---|---|
| Lowest per GPU/hr | $0.416/GPU/hr (cheapest overall) | $1.09/GPU/hr |
Which is better for AI: RTX 4090 or RTX 5090?
Both cards have FP8 tensor cores, so the real gap is memory: the RTX 5090 ships with 32GB of GDDR7 against the RTX 4090's 24GB (NVIDIA GeForce product pages, Aug 2026). That's 8GB more headroom for larger batch sizes or bigger models before you hit an out-of-memory error. Pick the RTX 5090 when you're VRAM-constrained: larger batches, bigger context windows, or models that don't quite fit in 24GB; pick the RTX 4090 when your workload already fits comfortably in 24GB and you'd rather bank the price difference. On price the RTX 4090 undercuts the RTX 5090 by 35% at the entry rate ($0.416 vs $0.642/GPU/hr). Worth weighing if the deciding factor above isn't a hard requirement for your job.
Decision criteria
| VRAM | 24 GB (RTX 4090) vs 32 GB (RTX 5090). 32GB GDDR7 vs 24GB GDDR6X per NVIDIA's own spec pages. |
| FP8 support | Both are FP8-capable (Ada Lovelace and Blackwell both clear the SM 8.9+ FP8 floor). |
| Architecture | Ada Lovelace (RTX 4090) vs Blackwell (RTX 5090). |
| Availability | 3 region(s) list the RTX 4090 vs 3 for the RTX 5090. |
| Entry price | $0.416/GPU/hr (RTX 4090) vs $0.642/GPU/hr (RTX 5090). |
Pick the RTX 4090 when
- Your model and batch size already fit in 24GB with headroom to spare
- You want the lower hourly rate and 5090 supply is thin in your region
- You're doing inference, not training, and don't need the extra VRAM
Pick the RTX 5090 when
- You're training or fine-tuning something that OOMs on 24GB
- You want more batch-size headroom for the same architecture
- You're future-proofing against growing context windows or model size
Price-performance
At list rates, 1,000 GPU-hours costs $416 on the RTX 4090 against $642 on the RTX 5090. Neither NVIDIA nor Aquanode publishes a workload-normalized $/token or $/epoch figure for this pair, so $/GPU-hour below is the only apples-to-apples number. A faster card can still cost less per finished job even at a higher hourly rate.
RTX 4090 vs RTX 5090: common questions
Is the RTX 4090 or the RTX 5090 better for AI?
Short answer: pick the RTX 5090 when you're VRAM-constrained: larger batches, bigger context windows, or models that don't quite fit in 24GB. Pick the RTX 4090 when your workload already fits comfortably in 24GB and you'd rather bank the price difference.
Is the RTX 4090 or the RTX 5090 cheaper to rent?
On Aquanode's live marketplace the RTX 4090 starts at $0.416/GPU/hr (median $0.753/GPU/hr) and the RTX 5090 starts at $0.642/GPU/hr (median $1.11/GPU/hr). The RTX 4090 is the cheaper of the two at the entry rate, by 35%.
What is the difference between the RTX 4090 and the RTX 5090?
The RTX 4090 has 24 GB of VRAM against the RTX 5090's 32 GB; the RTX 4090 is an Ada Lovelace part and the RTX 5090 is Blackwell (compute capability 8.9 vs 12.0); both run BF16, FP8, INT4 workloads in hardware. On price, the RTX 4090 lists from $0.416/GPU/hr and the RTX 5090 from $0.642/GPU/hr.
How widely available are the RTX 4090 and the RTX 5090?
The RTX 4090 is listed in 3 regions and the RTX 5090 in 3 regions right now.
How much does 1,000 GPU-hours cost on the RTX 4090 vs the RTX 5090?
At the lowest rates listed today, 1,000 GPU-hours costs $416 on the RTX 4090 and $642 on the RTX 5090, a difference of $226 for the same runtime. Rates are per GPU per hour and update hourly.
How much VRAM does the RTX 4090 have compared to the RTX 5090?
The RTX 4090 has 24 GB of VRAM; the RTX 5090 has 32 GB.
Does the RTX 5090 actually beat the RTX 4090 on more than VRAM?
Both cards have FP8 tensor cores, so neither has a compute-precision advantage the other lacks. The documented, vendor-confirmed difference this page can verify is memory: 32GB GDDR7 on the RTX 5090 versus 24GB GDDR6X on the RTX 4090. Any generational compute-throughput gap exists but isn't something Aquanode has benchmarked first-party, so it's left out rather than guessed.
Does the RTX 4090 or the RTX 5090 support NVLink?
Neither the RTX 4090 nor the RTX 5090 has a dedicated GPU-to-GPU interconnect.
How this comparison is calculated
Every price is normalized to a per-GPU hourly rate using the same pipeline as every other pricing surface on Aquanode, and only the cheapest qualifying offer per provider is shown. A dash means that provider does not currently list that GPU.
Architecture, compute capability and supported precisions come from each vendor's published datasheet for that generation, not from the marketplace feed. This page regenerates at most once per hour.
Memory bandwidth, tensor TFLOPS, NVLink/interconnect and max board power are the same verified-from-datasheet figures shown on each model's own RTX 4090 page and RTX 5090 page, which link the primary vendor source for that model. A dash here means Aquanode hasn't verified that figure from a primary source yet, never a guess.
Go further
Check what fits in each card's memory with the RTX 4090 VRAM calculator and the RTX 5090 VRAM calculator, or browse every model by generation in the GPU index.
More RTX 4090 comparisons
More RTX 5090 comparisons
Related reading: RTX 4090 pricing and specs, RTX 4090 for AI, RTX 5090 vs RTX 4090, and The best GPUs for AI, ranked.
