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Node Count and Capacity Definitions

Securing high-performance compute requires strict contractual precision before signing any commitment. When evaluating a cluster proposal, the headline number of GPUs often obscures the actual physical architecture delivered. A vendor quote advertising 64 GPUs can mean eight dedicated 8-GPU nodes tightly coupled in a private rack, or it can mean 64 disparate cards scattered across shared multi-tenant hosts. For distributed deep learning workloads utilizing Megatron-LM or PyTorch Fully Sharded Data Parallel (FSDP), that distinction dictates whether your training run scales linearly or stalls on cross-chassis communication.

Your agreement must explicitly define usable cluster nodes rather than raw silicon headcounts. A proper quote specifies the exact number of server chassis, the number of GPUs housed per chassis, and the dedicated compute host configuration (including host CPU architecture, system RAM per node, and local NVMe scratch capacity). Furthermore, the contract must include an ironclad dedicated capacity clause. Without dedicated hardware allocation, your workloads remain vulnerable to noisy-neighbor contention on PCIe buses and shared host memory, invalidating baseline performance benchmarks.

Essential Capacity Specifications to Validate

  • Node Topology: Exact ratio of GPUs per physical host (HGX H100 and H200 baseboards are offered in NVIDIA-Certified server configurations with 4 or 8 SXM GPUs) rather than arbitrary virtualized slicing.
  • Compute Isolation: Dedicated bare-metal or single-tenant virtualized nodes with zero resource sharing on host CPUs, PCIe root complexes, or memory channels.
  • Local Host Resources: Explicit allocation of host RAM sized for large checkpoints and dedicated PCIe Gen5 lanes.
  • Local NVMe Scratch: High-throughput local solid-state storage dedicated to caching datasets and fast local checkpointing.

Procuring infrastructure without these explicit node definitions forces engineering teams to diagnose cluster-level communication bottlenecks that originate in hardware mismatches. Failing to specify physical host hardware and networking boundaries upfront leads to operational friction and unexpected scaling bottlenecks during multi-node runs.

GPU Type and Baseboard Architecture

Vague references to accelerator families are a common pitfall in enterprise compute agreements. A quote that merely promises NVIDIA Hopper or Blackwell hardware fails to provide the technical constraints required to plan memory allocation, batch sizes, and parallelization strategies. The agreement must state the exact silicon variant and memory configuration, for example the H100 SXM5 with 80GB of HBM3 at 3.35 TB/s versus the H200 SXM5 with 141GB of HBM3e at 4.8 TB/s. The memory bandwidth and capacity differences between these revisions directly dictate whether your model fits into VRAM or triggers severe CUDA Out-of-Memory (OOM) failures during tensor parallel execution.

Equally critical is the baseboard form factor. A cluster built on PCIe add-in cards delivers drastically lower inter-GPU bandwidth compared to an HGX baseboard design using NVLink. PCIe Gen5 GPU connectivity is rated at 128 GB/s, while SXM5 Hopper GPUs provide 900 GB/s of NVLink GPU-to-GPU interconnect, with every GPU in an HGX H100 8-GPU node able to talk to any other at that full NVLink bidirectional speed. For tensor-parallel transformer models, running on PCIe baseboards introduces severe synchronization stalls during attention head computation.

Baseboard Architecture Comparison

Architecture ParameterNVIDIA HGX H100 (SXM5)NVIDIA PCIe H100NVIDIA HGX H200 (SXM5)
GPU Form FactorSXM5 BaseboardDual-Slot PCIe CardSXM5 Baseboard
VRAM per GPU80GB HBM380GB HBM3141GB HBM3e
VRAM Memory Bandwidth3.35 TB/s2.0 TB/s4.8 TB/s
Inter-GPU InterconnectNVLink 4 (900 GB/s)NVLink Bridge (600 GB/s) or PCIeNVLink 4 (900 GB/s)
Chassis Thermal RatingUp to 10.2 kW per 8-GPU NodeStandard Rack Air-CooledUp to 10.2 kW per 8-GPU Node

Evaluating these baseboard details protects your cluster from memory fragmentation and high latency during model sharding. High VRAM occupancy without matching inter-GPU bandwidth creates execution stalls where Streaming Multiprocessors sit idle while waiting for gradient synchronization. Verifying the exact baseboard and form factor in your quote guarantees that your software stack can fully utilize the theoretical TFLOPS of the hardware.

Network Interconnects and Topology

In multi-node distributed training, network performance dictates training throughput just as much as raw GPU compute. In distributed data parallel (DDP) and tensor-parallel jobs, GPUs must continuously synchronize weights and gradients across nodes using collective communication libraries such as NCCL. If the East-West interconnect cannot sustain line-rate bandwidth with near-zero latency, your GPUs will spend a substantial portion of their execution cycles waiting in AllReduce barriers.

Your quote must specify the exact network technology, switch models, and fabric topology. An enterprise AI cluster quote should clearly distinguish between InfiniBand and RDMA over Converged Ethernet (RoCE v2). For multi-node Hopper or Blackwell deployments, a common configuration uses NVIDIA Quantum-2 QM9700 switches, which deliver 64 non-blocking ports of NDR 400Gb/s InfiniBand and an aggregate bidirectional throughput of 51.2 Tb/s in a 1U chassis with adaptive routing. The quote must explicitly detail the host channel adapters (such as NVIDIA ConnectX-7 NICs) and state whether each GPU has a dedicated 400 Gb/s network interface for rail-optimized networking.

Fabric Verification Checklist

  • Interconnect Protocol: InfiniBand NDR (400 Gb/s) or RoCE v2 with full Lossless Ethernet configuration (PFC and ECN).
  • Switch Hardware: Explicit switch model numbers (for example, NVIDIA Quantum-2 QM9700 or QM9790 fixed-configuration switches).
  • Fabric Topology: Rail-optimized non-blocking Fat-Tree topology with a 1:1 oversubscription ratio across all compute leaf and spine layers.
  • NIC Allocation: Dedicated 400 Gb/s PCIe Gen 5 ConnectX-7 NIC per GPU to enable line-rate GPUDirect RDMA transfers without CPU traversal.
  • Telemetry and Diagnostics: In-band network telemetry, UFM (Unified Fabric Manager) access, and automated fabric health monitoring to catch degraded links.

When evaluating cluster proposals for multi-node workloads, treat network topology as a core compute constraint. A cluster with an oversubscribed 2:1 or 3:1 network fabric might offer a lower hourly rate on paper, but the resulting communication stalls will degrade training throughput by 30 to 50 percent, driving up the true cost per completed epoch.

Uptime SLAs vs Capacity Guarantees

Service level agreements in AI infrastructure require a fundamentally different evaluation framework than traditional cloud hosting. In standard web applications, a conventional per-instance uptime SLA is adequate because individual node failures are mitigated by load balancers. In distributed deep learning, training runs are tightly coupled: if a single GPU experiences an uncorrectable ECC memory error, a thermal throttle, or an NVLink link drop, the entire multi-node job crashes. An availability target calculated at the individual node level provides no practical guarantee that a multi-node distributed run will stay alive through a full training phase.

Production studies of large research clusters show that attributed hardware failures affect less than 1% of jobs but impact roughly 19% of GPU runtime, with backend InfiniBand links, filesystem mounts, GPU memory errors, and PCIe errors as the leading causes. Consequently, your agreement must differentiate between mere hardware reservation and operational cluster health. The quote must document the cluster-level availability metric, Mean Time to Detect (MTTD), Mean Time to Repair (MTTR), and the physical availability of on-site hot spares.

Key SLA Terms and Credit Realities

SLA DimensionStandard Cloud ClauseProduction Cluster RequirementEngineering Impact
Uptime ScopePer-node availability targetAtomic cluster availability (all nodes in job must be operational simultaneously)Prevents scenarios where nearly all nodes are online but the distributed job remains blocked.
Failure ResponseTicket response within business hoursAutomated node drainage and prompt hot-spare replacementEliminates multi-hour training stalls during overnight runs.
Service Credit StructureBilling credit on the affected instance onlyPro-rated credit covering the entire stalled cluster allocation for the outage durationEnsures service credits reflect the actual financial loss of lost multi-node compute time.
Maintenance WindowsUnilateral scheduled maintenance with short noticeCoordinated maintenance windows with checkpoint-save buffersPrevents unexpected cluster reboots during long-running convergence runs.

Remember that service credits are merely backward-looking billing adjustments, not operational insurance. They do not compensate your engineering team for wasted engineer hours, missed delivery milestones, or duplicated compute cycles caused by interrupted checkpoints. Ensure your contract includes automated hardware health monitoring, rapid node fencing, and direct access to low-level telemetry logs.

Location and Data Sovereignty

The physical location of the data centre housing your GPU cluster is both a regulatory boundary and a performance factor. For European enterprises, research institutions, and AI startups building proprietary foundation models, training on customer datasets introduces strict compliance mandates under the General Data Protection Regulation (GDPR) and emerging European AI governance frameworks. Deploying clusters in jurisdictions subject to extraterritorial surveillance legislation, such as the US CLOUD Act, exposes your proprietary training weights and sensitive training tokens to foreign legal discovery.

A compliant GPU cluster quote must state the exact facility address, country jurisdiction, and data centre tier (such as Tier III or Tier IV uptime certification). It must guarantee that all data at rest, data in flight, local scratch volumes, and persistent storage volumes remain strictly confined to the agreed sovereign jurisdiction. Furthermore, regional proximity ensures minimal network latency for engineering teams synchronizing large multimodal datasets or deploying real-time dedicated clusters for low-latency batch processing.

Data Sovereignty and Facility Audit Criteria

  • Jurisdictional Boundary: Data centre located within the European Economic Area (EEA), operated under local legal entities without foreign parent-company exposure.
  • Physical Security: Tier III or Tier IV certified facilities featuring biometric access control, 24/7 on-site physical security, and redundant N+1 or 2N power and cooling distribution.
  • Data Residency: Contractual guarantees that raw data, fine-tuning checkpoints, metadata, and cluster telemetry never leave the specified region.
  • Power Density and Redundancy: Facility-level confirmation of high-density rack support (up to 40-100 kW per rack for modern liquid-cooled AI systems) with dual utility feeds and backup generator capacity.

Demanding contractual certainty on data residency prevents costly forced migrations later when enterprise customers audit your training pipeline. Ensuring complete European data sovereignty at the infrastructure layer provides an indispensable operational foundation for building enterprise-grade AI products.

What Is Excluded: Egress and Storage

One of the most frequent financial surprises in AI infrastructure procurement is the gap between the quoted GPU hourly rate and the final monthly invoice. The headline price per GPU hour often represents only the raw silicon allocation. Legacy hyperscalers and unbundled hosting providers frequently omit supporting infrastructure components that are mandatory to operate the cluster, creating a deceptive total cost of ownership profile.

Data transfer fees represent the largest hidden operational tax. Traditional cloud vendors charge per-gigabyte cloud egress fees when moving data, logs, or model weights out of the cluster or between cloud regions. For a computer vision or multimodal LLM training pipeline pulling hundreds of terabytes of data each week, egress charges can add a substantial recurring line to the monthly bill. Your quote must state zero-egress terms or explicitly cap data transfer costs.

Common Quote Omissions Checklist

  • Data Egress Fees: Network egress charges for moving training checkpoints, container images, and dataset shards outside the provider's local virtual private cloud (VPC).
  • Parallel File Storage: High-throughput shared storage systems (such as Lustre, Weka, or parallel NFS) sized to feed the cluster and keep GPUs saturated without I/O wait states.
  • InfiniBand Fabric Uplinks: Switch port licensing, inter-rack optical cabling, and fabric management software licensing fees.
  • Power and Cooling Overhead: Facility power delivery surcharges or supplementary cooling fees added onto bare-metal lease agreements.
  • Support and Setup Fees: Professional onboarding fees, private VPC peering setup, or mandatory premium support tiers required to access technical escalation.

A comprehensive financial audit must demand an all-inclusive quote structure. If storage throughput, networking ports, or data egress are billed as variable meters, your team cannot reliably forecast infrastructure spend or maintain predictable operating margins.

Availability Date and Payment Terms

The timeline of GPU delivery is just as critical as the hardware specification. In a constrained hardware market, quotes frequently promise allocations that are contingent on future data centre buildouts or unverified supplier pools. A vague commitment such as "estimated deployment Q3" leaves your engineering team stranded without compute while payroll and operational timelines advance. A binding quote must specify a firm, non-contingent handover date with contractual remedies if delivery milestones are missed.

Commercial structures must also be scrutinized. Traditional hardware brokers demand 20 to 30 percent upfront down payments and 12- to 36-month rigid commitments, transferring hardware depreciation risk onto the buyer. For teams with dynamic iteration cycles, modern infrastructure agreements should provide flexible commitment tiers, predictable monthly invoicing, or transparent per-second billing models that eliminate idle hardware waste.

Contractual Checklist Before Signing

  • Guaranteed Delivery Milestone: Exact, binding hardware handover date with clear SLA remedies or penalty credits for provisioning delays.
  • Clear Commitment Terms: Transparent contract length (ranging from flexible 3- to 12-month sweet spots up to multi-year reservations) with defined scale-down terms.
  • Payment Structure: Clear documentation of deposit requirements, payment milestones, and billing intervals (monthly invoicing or per-second billing).
  • Testing and Acceptance Window: A contractual 48-hour to 7-day burn-in period to run NCCL tests, bandwidth verification, and stress benchmarks before billing officially commences.

At Lyceum, we build infrastructure for European AI teams that demand complete technical transparency, sovereign EU data hosting, and straightforward commercial terms. Rather than navigating hidden fees and opaque hosting layers, you can review our live transparent pricing or use our interactive GPU pricing calculator to evaluate your infrastructure requirements. When your team is ready to deploy dedicated multi-node compute with guaranteed network topology and verified delivery timelines, consult our live pricing page and request a same-day quote.