Quick answer: The H100 and H200 run the same GH100 die pair at the same clocks — the only difference is memory, 80 GB of HBM3 at 3.35 TB/s versus 141 GB of HBM3e at 4.8 TB/s. B200 is a new generation: two dies per package, 180 GB of HBM3e at 8 TB/s, roughly double the dense FP16 compute, NVLink 5, and about 1 kW per card. If your models fit in 80 GB per GPU, an H100 SXM is the simplest buy. If weights plus KV cache need more than that, the H200 saves you a second card per replica. If you need Blackwell-class compute density, budget for liquid cooling before you budget for anything else.
This guide deliberately contains no prices. Accelerator quotes move week to week with condition grade, memory configuration, batch size and destination, so any number printed here would be wrong by the time you read it. What does not move is the specification and the procurement logic — which is what decides whether a quote is good.
The spec sheet
Vendor figures, dense (sparsity off).
| Card | HBM | Bandwidth | FP16 / BF16 dense | Card interconnect | TDP | Form factor |
|---|---|---|---|---|---|---|
| A100 80 GB | 80 GB HBM2e | 2,039 GB/s | 312 TFLOPS | 600 GB/s NVLink | 400 W | SXM4 |
| H100 80 GB PCIe | 80 GB HBM2e | 2,000 GB/s | 756 TFLOPS | 600 GB/s bridge, 2-way | 350 W | PCIe |
| H100 80 GB SXM5 | 80 GB HBM3 | 3,350 GB/s | 989 TFLOPS | 900 GB/s NVLink | 700 W | SXM5 |
| H200 141 GB SXM | 141 GB HBM3e | 4,800 GB/s | 989 TFLOPS | 900 GB/s NVLink | 700 W | SXM5 |
| B200 180 GB SXM | 180 GB HBM3e | 8,000 GB/s | ~2,250 TFLOPS | 1,800 GB/s NVLink 5 | ~1,000 W | SXM |
| L40S 48 GB | 48 GB GDDR6 | 864 GB/s | 366 TFLOPS | None (PCIe only) | 350 W | PCIe |
| MI300X 192 GB | 192 GB HBM3 | 5,300 GB/s | 1,307 TFLOPS | 896 GB/s Infinity Fabric | 750 W | OAM |
Two rows are easy to overlook. The H100 PCIe is not a slower H100 SXM — it is a different memory subsystem (HBM2e at 2 TB/s) and a different fabric story: two-way only, 600 GB/s, with no path to an eight-card all-to-all mesh. And the L40S has no card-to-card interconnect at all, which is fine for inference and rendering and disqualifying for anything that needs tensor parallelism across eight GPUs.
If you are specifying a PCIe platform, note that NVL variants exist: H100 NVL at 94 GB (3.9 TB/s, up to 400 W) and H200 NVL at 141 GB (600 W). Both are PCIe cards bridged in pairs, not in an eight-way mesh.
The ratios that decide the fit
Prices change; these ratios do not. They are computed from the table above, so you can check any quote against them.
| Card | FP16 TFLOPS per 100 W | GB/s of bandwidth per GB of HBM | TFLOPS per GB of HBM |
|---|---|---|---|
| A100 80 GB | 78 | 25.5 | 3.9 |
| H100 80 GB PCIe | 216 | 25.0 | 9.5 |
| H100 80 GB SXM5 | 141 | 41.9 | 12.4 |
| H200 141 GB SXM | 141 | 34.0 | 7.0 |
| B200 180 GB SXM | 225 | 44.4 | 12.5 |
| L40S 48 GB | 105 | 18.0 | 7.6 |
| MI300X 192 GB | 174 | 27.6 | 6.8 |
Read with your bottleneck in mind, because the winners are different.
- Capacity-bound work — large models, long context, many concurrent sequences — is decided by HBM per card and by TFLOPS per GB of HBM. The low end of that last column is the point: MI300X and H200 carry the most memory for the compute they bring, which is exactly what you want when the GPU is mostly holding weights and KV cache.
- Bandwidth-bound work — token generation on any transformer — is decided by bandwidth per GB of HBM. H100 SXM and B200 lead here, which is why a 3.35 TB/s H100 SXM usually beats a 2.0 TB/s H100 PCIe at the same model size, despite identical model names.
- Power- or rack-constrained work is decided by TFLOPS per watt and by bandwidth per watt. L40S and A100 sit at the bottom; Blackwell sits at the top and costs you cooling to get there.
And the one column that is not in the table: fabric. A card with no NVLink is not a cheaper version of a card with NVLink, it is a different platform, and no ratio will tell you that.
H100 vs H200: same compute, different memory
Strip the labels and the H200 is an H100 SXM with 61 GB more HBM3e and 43% more bandwidth. Same GH100 die pair, same 989 TFLOPS dense, same 900 GB/s NVLink, same 700 W. Everything that changes is memory.
That is exactly the axis that governs inference economics in 2026. Token generation is memory-bandwidth-bound: every token requires reading the full weight set plus the KV cache, so tokens per second scale roughly with bandwidth per GPU, and concurrency scales with capacity. Going from 3.35 TB/s to 4.8 TB/s is a 43% headroom increase on the number that sets your serving throughput — before you count the fact that you can hold a larger KV cache for the same model on the same card.
Where the H200's extra memory does not earn its place: models under ~20B parameters with short context (both cards fit them several times over), fine-tuning jobs where step time is compute-bound rather than bandwidth-bound, and anything where you can shard across more nodes cheaply. In those cases an H100 SXM build with more cards usually beats a smaller H200 build — more cards buy more parallelism, and parallelism is what most training and batch workloads are actually short of.
The 70B test
For a 70B parameter model at FP16, the weights alone are about 140 GB. One H200 holds them with room for KV cache. One H100 80 GB does not — that design needs two cards per replica, or FP8 quantisation, or model sharding with the associated interconnect traffic.
Two H100 SXM cards also mean 1,400 W of accelerator power and two failure surfaces for one replica, against 700 W and one card for the H200. That is the real comparison: it is not "80 GB versus 141 GB", it is "one card versus two, in the same chassis budget, on the same baseboard generation". Run the same calculation for your own model size before you pick, because it flips at different points for 7B, 20B and 70B weights.
B200: double the compute, and a power problem
B200 is the first Blackwell part most buyers will actually quote. Two dies in one package, 180 GB HBM3e at 8 TB/s, ~2.25 PFLOPS dense FP16, NVLink 5 at 1.8 TB/s, around 1 kW per card. It is roughly double the H100's compute and more than double its bandwidth, and it is the only card in this table where the compute increase outruns the memory increase.
The constraint moves with it. Eight B200 cards draw about 8 kW before CPUs, NICs and drives; a full node lands at 10–12 kW, and eight such nodes put 80–96 kW in a rack. Air-cooled density tops out well below that, so a B200 decision is a facilities decision: liquid cooling, power provisioning at the colo and per-rack limits become the binding constraint before the budget does. H100 and H200 nodes sit at roughly 7 kW each, which is why so many 2026 builds still specify Hopper — not because it is cheaper per FLOP, but because the datacenter can cool it.
Supply is the other half. B200 is largely allocated through OEM and distributor channels; genuine secondary supply is thin and should be treated with suspicion. Lead times of 12–20 weeks are normal, and an allocation slot is not the same thing as stock on a shelf. Blackwell Ultra (B300, 288 GB at 1.4 kW) is the next planning point, and it lands in the same power envelope problem.
What an 8-card node actually contains
The most common sourcing mistake is quoting cards and forgetting the platform. An 8-GPU SXM node is a matched set, and the parts are generation-specific.
| Line item | Qty | Why it matters | Interchangeable across generations? |
|---|---|---|---|
| H100 / H200 / B200 SXM module | 8 | The accelerators themselves | No — baseboard and power differ by generation |
| HGX baseboard | 1 | Carries the SXM modules and the NVSwitch fabric | No |
| Host CPU (Xeon 6 or EPYC 9004) | 2 | Feeds eight GPUs; rarely the bottleneck | Yes, within socket/platform limits |
| DDR5 RDIMM, 64 GB | 32 | 2 TB for KV cache offload, dataset staging, CPU inference | Yes |
| 400G NIC (ConnectX-7 class) | 8 | One per GPU for east-west traffic | Usually yes |
| NVMe U.2, 3.84 TB | 8 | Local scratch and model cache | Yes |
| Chassis, 8× PSU, power shelf, cooling | 1 | Sets the kW ceiling and the acoustic profile | No |
Two procurement notes follow. First, quote the node, not the cards — an SXM5 module is not a PCIe card, it needs an HGX baseboard, a matching power shelf and a chassis with the right thermal design, and those parts are not interchangeable between H100 and B200 generations. Second, treat memory as an accelerant of the schedule, not an afterthought: server DRAM has been volatile through 2026, as our DDR4 vs DDR5 bulk cost breakdown explains, and 32 DIMMs per node is not a rounding error — that line is priced off the server memory line and it moves weekly.
The composition of an 8-GPU node is stable even though the numbers are not: accelerators dominate the build, memory is the second-largest line item in a way it was not in 2023, and the CPU that people argue about most is the smallest of the three.
Which card for which workload
Every card in this table is quoted from held stock in Hong Kong, and current batches are listed on the data-centre GPU line.
| Workload | Card | Why | Node shape |
|---|---|---|---|
| Long-context inference, 70B+ | H200 141 GB | Weights plus KV cache fit in one card; bandwidth sets token rate | 8× SXM |
| Standard inference, ≤20B models | H100 SXM or L40S | Capacity is not the constraint; L40S needs no fabric | 8× SXM or 4× PCIe |
| Fine-tuning, 7B–70B | H100 SXM | Compute-bound steps; more cards beat better cards | 8× SXM |
| Frontier training | B200 / B300 | Only class with the compute and NVLink 5 bandwidth | 8× SXM, liquid |
| VDI, rendering, light inference | L40S | No need for NVLink; 48 GB handles most graphics workloads | 2–8× PCIe |
| Maximum memory per card | MI300X or H200 | Capacity-bound workloads; MI300X has the largest pool | 8× OAM / SXM |
| Legacy or budget inference | A100 80 GB | Still the cheapest way to run older models at scale | 8× SXM4 |
What the used market gets wrong
Three failure modes account for most of the disputes we see in bulk GPU orders, and all three are detectable before payment.
- Hours that do not exist.
nvidia-smidoes not report GPU-on hours. A supplier who quotes them "from nvidia-smi" has invented them; the real sources are donor-chassis BMC power-on logs and the OEM warranty start date, which should corroborate each other. - SXM modules sold as standalone cards. Hopper SXM5 parts are baseboard components. If a quote offers "H100 SXM, works in any server", the unstated part of the deal is that you also need an HGX baseboard, power shelf and chassis — or that the module came off one and has an unknown interconnect history.
- Cosmetic refurbishment as health. Fresh thermal pads and paste make a card look serviced and change its thermal signature. Sustained two-to-four-hour load runs, with the clock and thermal curve logged, are what separate maintenance from concealment.
The verification routine covers the countermeasures in full: aggregate ECC counters, row-remap and page-retirement state, serial lists in the PO, and NCCL bandwidth against a reference group.
