AMD MI300X vs RTX 4090: Specs, VRAM & Price
Short answer: choose the AMD MI300X when 192 GB of VRAM is the gating requirement. Choose the RTX 4090 when 24 GB is enough for the workload and the lower hourly rate points that way.
The AMD MI300X has 192 GB of VRAM; the RTX 4090 has 24 GB.
You can rent both by the hour, no purchase required. AMD MI300X from $3.29/GPU/hr; RTX 4090 from $0.587/GPU/hr. The RTX 4090 is 82% cheaper at the entry rate.
AMD MI300X
Good for training and serving frontier-scale LLMs
RTX 4090
Good for inference and light fine-tuning workloads
Last updated: 2026-10-16 UTCRefreshes every 6 hours
Specs side by side
| Spec | AMD MI300X | RTX 4090 |
|---|---|---|
| VRAM | 192 GB | 24 GB |
| Memory bandwidth | 5.3 TB/s | 1,008 GB/s |
| Architecture | CDNA3 | Ada Lovelace |
| Compute capability | n/a | 8.9 |
| Precisions in hardware | FP32, FP16, BF16, FP8, INT4 | FP32, FP16, BF16, FP8, INT4 |
| Peak FP16/BF16 tensor TFLOPS | 1,307.4 TFLOPS | – |
| Peak FP8 tensor TFLOPS | 2,614.9 TFLOPS | – |
| NVLink / multi-GPU interconnect | Infinity Fabric | – |
| Max board power (TDP) | 750W | 450W |
| Form factor | – | PCIe 4.0 x16 |
| Regions | 1 | 2 |
On-demand price
| Rate | AMD MI300X | RTX 4090 |
|---|---|---|
| Lowest per GPU/hr | $3.29/GPU/hr | $0.761/GPU/hr |
Which is better for AI: AMD MI300X or RTX 4090?
Choose the AMD MI300X when 192 GB of VRAM is the gating requirement. Choose the RTX 4090 when 24 GB is enough for the workload and the lower hourly rate points that way.
AMD MI300X vs RTX 4090: common questions
Is the AMD MI300X or the RTX 4090 better for AI?
Short answer: choose the AMD MI300X when 192 GB of VRAM is the gating requirement. Choose the RTX 4090 when 24 GB is enough for the workload and the lower hourly rate points that way.
Is the AMD MI300X or the RTX 4090 cheaper to rent?
On Aquanode's live marketplace the AMD MI300X starts at $3.29/GPU/hr (median $3.29/GPU/hr) and the RTX 4090 starts at $0.587/GPU/hr (median $0.994/GPU/hr). The RTX 4090 is the cheaper of the two at the entry rate, by 82%.
What is the difference between the AMD MI300X and the RTX 4090?
The AMD MI300X has 192 GB of VRAM against the RTX 4090's 24 GB; the AMD MI300X is a CDNA3 part and the RTX 4090 is Ada Lovelace; both run BF16, FP8, INT4 workloads in hardware. On price, the AMD MI300X lists from $3.29/GPU/hr and the RTX 4090 from $0.587/GPU/hr.
How widely available are the AMD MI300X and the RTX 4090?
The AMD MI300X is listed in 1 region and the RTX 4090 in 2 regions right now.
How much does 1,000 GPU-hours cost on the AMD MI300X vs the RTX 4090?
At the lowest rates listed today, 1,000 GPU-hours costs $3,289 on the AMD MI300X and $587 on the RTX 4090, a difference of $2,702 for the same runtime. Rates are per GPU per hour and update hourly.
How much VRAM does the AMD MI300X have compared to the RTX 4090?
The AMD MI300X has 192 GB of VRAM; the RTX 4090 has 24 GB.
Does the AMD MI300X or the RTX 4090 support NVLink?
The AMD MI300X supports Infinity Fabric; the RTX 4090 has no 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 AMD MI300X page and RTX 4090 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 AMD MI300X VRAM calculator and the RTX 4090 VRAM calculator, see vendor-published throughput in the GPU benchmarks and specs table, or browse every model by generation in the GPU index.
More AMD MI300X comparisons
More RTX 4090 comparisons
Related reading: AMD MI300X pricing and specs, ROCm vs CUDA, AMD vs NVIDIA GPUs for AI, AMD MI355X guide, and The best GPUs for AI, ranked.
