RTX 5090 vs H100 80GB
The H100 80GB holds 50 models from our catalog that the RTX 5090 cannot fit at Q4_K_M, and decodes about 1.9× faster on memory bandwidth. Decode speed on a memory-bound workload scales with bandwidth, so that ratio is the number that matters once the model fits at all.
Specs side by side
| Spec | RTX 5090 | H100 80GB |
|---|---|---|
| VRAM | 32 GB | 80 GB |
| Memory bandwidth | 1792 GB/s | 3350 GB/s |
| TDP | 575 W | 700 W |
| Models that fit (Q4_K_M) | 423 of 506 | 473 of 506 |
Form factor: H100 80GB figures are for the SXM5 module. PCIe/NVL variants differ in bandwidth and TDP — see the H100 80GB page and methodology.
What the extra VRAM actually buys
50 models in our catalog fit on the H100 80GB at Q4_K_M but not on the RTX 5090. The largest of them:
Pixtral Large 124B InstructMistral Large 123B (2407) InstructMistral Large 123B (2411) InstructGPT-OSS 120B (5.1B active) InstructCommand A 111B ChatQwen 1.5 110B
Largest model each can run
At Q4_K_M the biggest fit in our catalog is Nemotron Super 49B Instruct (29.8 GB) on the RTX 5090, and Pixtral Large 124B Instruct (74.3 GB) on the H100 80GB. Both figures are weights plus runtime overhead; KV cache for your context is extra.
Power and running cost
At 8 hours a day the RTX 5090 draws about 138 kWh a month against 168 kWh for the H100 80GB — a difference of 30 kWh. Multiply by your own tariff; we do not assume one. Board TDP is the rated figure, not measured draw.
FAQ
RTX 5090 vs H100 80GB: which should I buy for local AI?
The H100 80GB fits 473 of the 506 models in our catalog at Q4_K_M against 423 for the RTX 5090, and has about 1.9× the memory bandwidth, which is what sets decode speed once a model fits. If the models you run already fit the RTX 5090, the extra spend buys context length and speed, not a new model tier.
Is the H100 80GB faster than the RTX 5090?
On memory-bound decoding, yes — roughly 1.9× the throughput, since token generation scales with memory bandwidth (3350 GB/s vs 1792 GB/s). This is an upper bound from bandwidth alone, not a measured benchmark.
How much more VRAM does the H100 80GB have?
48 GB more (80 GB vs 32 GB). That difference lets it hold 50 additional models from our catalog at Q4_K_M.
Need a third card in the mix? The interactive compare tool lines up any three. To size KV cache for your context length, use the GPU Memory Calculator.
Related matchups
Other head-to-heads involving these cards:
RTX 4090 vs RTX 5090RTX 3090 vs RTX 5090RTX 5090 vs RTX A6000A100 80GB vs H100 80GBH100 80GB vs H200 141GB
New to sizing? What VRAM is and why bandwidth sets decode speed cover the basics, and quantization explains the formats in the table above. Common mistakes when sizing VRAM lists the traps.