September 25, 2026
Choose a provider that will serve your own weights on single-tenant B200 or B300 GPUs, tune the inference engine for that specific model, and show measured results against latency numbers you have written down in advance. GMI Cloud Prime Inference is built for dedicated, tuned serving: single-tenant GPUs, runtimes tuned to open-source or your own model, per-model kernel, scheduling, and routing optimization, configurable quantization, weights kept warm, and endpoints pinned to the region closest to your users. B200 and B300 are in pre-order on GMI Cloud, so this is capacity you reserve now; H200 is available today for your latency baseline. Our engineering team works with you from prototype to production.
While Blackwell capacity is scheduled, H200 is the right place to build that baseline and your quality gate. What turns "tuned for your model" from a sales phrase into something you can check is three things: a written latency spec, a clear reason for B200 or B300, and a tuning plan with evidence attached to each item.
"Low latency" is not a target anyone can tune toward. A target with percentiles, load, and request shape is. Write the spec before the first provider conversation, because every tuning decision that follows is a trade between these fields.
| Field | What to write down | Why it matters |
|---|---|---|
| Time to first token (TTFT) | p50 and p99 at your target concurrency | Prefill cost grows with prompt length, so TTFT means little without the input lengths behind it |
| Inter-token latency (ITL, also called TPOT) | p50 and p99, and whether the first token is excluded | NVIDIA's LLM benchmarking guide notes that tools differ on whether ITL includes the first token |
| Concurrency floor | The number of simultaneous streams at which both targets must still hold | Almost any setup meets its targets at one stream |
| Request shape | Distribution of prompt and completion lengths from real traffic | Shifts the balance between prefill and decode work |
| Measurement point | Client side in a named region, or server side | NVIDIA's guide counts queuing, prefill, and network time inside TTFT |
| Quality floor | Your eval set and the pass threshold | Guards every precision or decoding change the provider makes |
A usable spec reads like a single sentence: p99 TTFT under X ms and p99 ITL under Y ms at N concurrent streams, measured at the client in a named region, for the prompt and completion lengths in the attached sample, with eval scores no lower than Z.
On a single node, latency is shaped mostly by two things: how many GPUs each model replica spans, known as the tensor parallel (TP) width, and how much memory is left for KV cache once the weights are loaded. B200 and B300 differ on both.
NVIDIA's HGX specifications list 2.1 TB of GPU memory per 8-GPU HGX B300 board against 1.4 TB for HGX B200. The two share the same fifth-generation NVLink bandwidth and the same listed FP8 throughput. HGX B300 lists about 1.5x the dense FP4 throughput and 2x the attention performance of the original Blackwell (B200), per NVIDIA. On our Prime Inference page, B300 is described as offering the maximum memory per GPU, for trillion-parameter models, ultra-long context, and the highest-throughput FP4 inference, when B200 isn't enough.
That gives a practical rule:
TP width works in both directions. A wider replica splits each token's math across more GPUs but adds communication at every layer. The right width for your model is something the provider measures at your concurrency floor, not something to assume.
Tuning is a set of decisions, and each one should come with evidence you can check against your spec. This is the checklist to agree on before reserving capacity.
| Tuning item | What the provider does | Evidence to accept |
|---|---|---|
| Precision (FP8, FP4) | Picks the lowest precision that passes your quality floor | Eval scores and latency at each precision tried, on your eval set |
| TP width and replica layout | Compares replicas of 2, 4, or 8 GPUs | TTFT and ITL at your concurrency floor for each layout |
| Speculative decoding | Tests a draft model or other speculative method and tunes draft length | Acceptance rate on your traffic, plus ITL at the concurrency floor and at peak |
| Batch size and concurrency cap | Sets maximum concurrent sequences and batched tokens so p99 holds | A latency-versus-concurrency curve with the chosen cap marked |
| Prefill and decode scheduling | Sizes prefill chunks and sets priorities so long prompts do not stall streaming | p99 ITL with long-prompt requests mixed into the load |
| Warm-up | Loads weights and prepares kernels before traffic arrives | First requests after a deploy or restart match steady-state latency |
Two of these deserve a closer look.
Speculative decoding can cut ITL sharply for some models and traffic, and barely help for others. vLLM, SGLang, and TensorRT-LLM all document speculative decoding, but the gain depends on how often the draft tokens are accepted, and it usually shrinks as batches grow. Ask for results at both your concurrency floor and your peak, and for a quality check on the same eval set.
The concurrency cap is where latency and cost meet. Letting more sequences share a replica raises throughput and lowers cost per token, but it pushes p99 ITL up. The provider should show you the curve and the point they picked, so the trade is visible rather than buried in a config file.
Ask for a short report at the end of tuning: the engine and version, precision, TP width, replica count, speculative settings, concurrency cap, and measured TTFT and ITL percentiles against your spec. That report is also your baseline for every later model update.
Prime Inference is our dedicated inference service on reserved NVIDIA GPUs. Here is what it provides for a latency-sensitive custom model:
Because B200 and B300 are in pre-order, the region that will host your endpoint and the tuning items in scope beyond our per-model runtime work are planned with our engineering team. Ask for the measurement method and sign-off criteria for your latency spec to be written into the deployment scope. Uptime SLAs are determined by GPU series, deployment configuration, and contract.
The latency spec, eval set, and traffic sample do not depend on Blackwell, so there is no reason to wait for them.
Can a latency target be part of the deployment agreement? Bring the target as a written spec with percentiles, concurrency, request shape, and measurement point. Include the measurement method and sign-off criteria in the deployment scope. Uptime SLAs are set separately, by GPU series, configuration, and contract.
Is B300 always lower latency than B200? No. For a model that already fits on B200 at the TP width your ITL target needs, the listed FP8 throughput and NVLink bandwidth are the same on both. B300 earns its place through memory headroom, FP4 throughput, and attention performance on long prompts.
Can we use our own draft model for speculative decoding? The engines Prime Inference runs support speculative decoding. Whether it is part of your deployment, and with which draft model, is confirmed during planning and should be validated against your eval set.
Bring your latency spec, eval set, and traffic profile, and talk to our team about a B200 or B300 pre-order and the tuning scope for your model. To start measuring now, deploy your model on H200 from the GMI Cloud console.
Colin Mo
GMI Cloud helps you architect, deploy, optimize, and scale your AI strategies
