Short answer: AMD Instinct MI300X offers 192GB HBM3 per accelerator, while NVIDIA H200 offers 141GB HBM3e. The extra 51GB lets MI300X hold some artifacts with materially more device headroom, but capacity alone does not select a winner. Choose from the exact model, ROCm-versus-CUDA support, server platform, multi-accelerator topology, measured throughput, power and complete deployment cost.
Neither product is a normal desktop GPU. MI300X is a passive OAM accelerator for qualified server platforms. H200 SXM belongs in HGX-class systems, while H200 NVL is a dual-slot air-cooled PCIe product for qualified MGX systems. Buying a bare module does not provide a usable local-AI server.
MI300X vs H200 specifications
| Decision factor | AMD Instinct MI300X | NVIDIA H200 |
|---|---|---|
| Architecture | AMD CDNA 3 (gfx942) | NVIDIA Hopper (GH100; compute capability 9.0) |
| Memory per accelerator | 192GB HBM3 with full-chip ECC | 141GB HBM3e |
| Published bandwidth | 5.3TB/s maximum peak theoretical | 4.8TB/s |
| Primary software lane | ROCm | CUDA |
| Form factor | Passive OAM module | SXM, or H200 NVL dual-slot air-cooled PCIe for qualified systems |
| Published power | 750W maximum TBP | SXM configurable up to 700W; NVL configurable up to 600W |
| Eight-accelerator memory | 1.5TB aggregate HBM3 on the MI300X platform | 1.1TB aggregate HBM3e on HGX H200 |
Qwen3.5-122B fit: where 192GB changes the answer
| Complete artifact | Files | H200 141GB | MI300X 192GB |
|---|---|---|---|
| Official GPTQ-Int4 | 78.864GB | Fits by files with substantial capacity margin | Fits by files with larger capacity margin |
| Community Q4_K_M + F16 projector | 77.446GB | Fits by files; verify projector and runtime placement | Fits by files; verify projector and runtime placement |
| Official FP8 | 127.163GB | Fits by files, but only 13.837GB nominal decimal margin remains | Fits by files with 64.837GB nominal decimal margin |
| Community Q8_0 + F16 projector | 130.781GB | Fits by files, but only 10.219GB nominal decimal margin remains | Fits by files with 61.219GB nominal decimal margin |
| Official BF16 | 250.173GB | Does not fit on one accelerator | Does not fit on one accelerator |
Qwen3.5-397B requires multiple accelerators
| Official artifact | Files | Minimum H200 nominal aggregate | Minimum MI300X nominal aggregate |
|---|---|---|---|
| GPTQ-Int4 | 235.708GB | 2×141GB = 282GB | 2×192GB = 384GB |
| FP8 | 406.152GB | 3×141GB = 423GB, a tight aggregate file boundary | 3×192GB = 576GB |
| BF16 | 806.796GB | 6×141GB = 846GB, a tight aggregate file boundary | 5×192GB = 960GB |
ROCm versus CUDA is a workload test, not a slogan
MI300X requires an exact ROCm-supported operating system, container, framework, gfx942 kernels, quantization path and model architecture. H200 requires the matching NVIDIA driver, CUDA toolkit, Hopper kernels, framework and extensions. A framework name appearing on both platforms does not prove identical operator coverage, numerical behavior or speed.
- Verify Qwen3.5 MoE routing, hybrid attention, MTP, multimodal projector and chosen precision on the exact runtime release.
- Record container digest, driver, toolkit, framework, model revision and quantization.
- Run a fixed prompt-processing and generation workload before comparing results.
- Treat vendor peak FLOPS and bandwidth as specifications, not observed token rates.
Multi-accelerator topology decides whether aggregate memory is useful
AMD’s eight-accelerator MI300X platform provides 1.5TB aggregate HBM3 with fully meshed Infinity Fabric connectivity. NVIDIA’s HGX H200 reference platform provides about 1.1TB aggregate HBM3e across eight GPUs with NVLink/NVSwitch. Those totals do not appear as one device. The runtime must implement tensor, pipeline, expert or layer placement, and communication can dominate a poor split.
For every result, report per-device placement, local peak memory, topology, interconnect traffic, CPU/system-memory offload, context, batch size and concurrency. The benchmark builder includes fields for those details.
Power and acquisition comparisons need the complete system
MI300X’s 750W figure, H200 SXM’s configurable-up-to-700W figure and H200 NVL’s configurable-up-to-600W figure describe accelerator limits, not wall power for an equivalent inference job. A complete server also powers CPUs, host memory, storage, networking, fans or liquid cooling, and power-conversion losses. Compare measured wall energy for the same workload and include the qualified platform, warranty and support—not a bare-module listing.
A defensible selection sequence
- Name the exact model repository, revision, files, precision and projector.
- Confirm the production runtime on the exact ROCm or CUDA software stack.
- Choose one- or multi-accelerator placement and calculate local—not only aggregate—headroom.
- Verify the complete qualified server, topology, cooling, power, firmware and management path.
- Benchmark identical context, input modality, output length, batch size and concurrency.
- Measure peak device/system memory, time to first token, prompt processing, generation, errors, throttling and wall power.
- Compare complete acquisition or hosting cost and operational support.
Continue with the MI300X guide, H200 guide, Qwen3.5-122B guide, Qwen3.5-397B guide, 96GB-to-1TB hardware paths, multi-GPU memory guide, workload test or private watchlist/RSS page.
Primary sources
- AMD Instinct MI300X specifications
- AMD MI300X datasheet
- AMD MI300X platform acceptance guide
- NVIDIA H200 product page
- NVIDIA HGX H200 reference architecture
- HighVRAM methodology
Reviewed October 25, 2026. Specifications are manufacturer-published. HighVRAM has not independently benchmarked every platform, runtime or workload. Arithmetic file fit does not establish compatibility, speed, quality, reliability or value.
Next-generation capacity comparison: the MI325X versus B200 guide moves this cross-vendor decision to 256GB AMD and 180GB NVIDIA tiers with exact Qwen3.5 file boundaries.
\n\nWould 256GB on one AMD accelerator change the placement? Continue with the MI325X 256GB guide, including one-device 397B 4-bit boundaries and the 2.048TB platform.
AMD’s newer 288GB option is covered in the MI350X vs MI355X local-AI guide, including its different cooling and power requirements.
Choosing among AMD generations? Compare MI300X, MI325X, MI350X and MI355X before selecting the NVIDIA comparison point.