AI Racks Explained

/specs

Specifications and sources

Every figure below was read from its source on 2026-10-13. A figure is either stated by the vendor, derived from stated figures (the formula is in the model), or not disclosed in the sources used: gaps are never filled with a guess. Hover a source tag for the source's title, its access date and where in it the figure is. Availability: product (a vendor product page lists the specifications), preliminary (the vendor marks them preliminary or projected), planned (the vendor gives a future date). The same table, generated by the model's script, is results.md.

GPUs

 H100 SXM5H200 SXMBlackwell (GB200 NVL72)Blackwell Ultra (GB300 NVL72)Rubin (Vera Rubin NVL72)preliminary
BF16, dense990 TFLOP/s (derived)[h100-page]990 TFLOP/s (derived)[h200-page]2,500 TFLOP/s (derived)[gb200-page]2,500 TFLOP/s (derived)[gb300-page]4,000 TFLOP/s[vr-page]
FP8, dense1,980 TFLOP/s (derived)[h100-page]1,980 TFLOP/s (derived)[h200-page]5,000 TFLOP/s[bwu-blog]5,000 TFLOP/s[bwu-blog]17,500 TFLOP/s[vr-page]
Compute dies1[bwu-blog]1[bwu-blog]2[bw-arch]2[bwu-blog]not disclosed[vr-page]
HBM bandwidth3.35 TB/s[h100-page]4.8 TB/s[h200-page]8 TB/s (derived)[gb200-page]8 TB/s[bwu-blog]19.2 TB/s[vr-page]
HBM capacity80 GB[h100-page]141 GB[h200-page]186 GB (derived)[gb200-page]288 GB[bwu-blog]288 GB[vr-page]
HBM stacks5[hopper-blog]not disclosed[h200-page]not disclosed[bwu-blog]8[bwu-blog]not disclosed[vr-page]
NVLink per GPU (both directions)900 GB/s[nvlink-page]900 GB/s[h200-page]1.8 TB/s[nvlink-page]1.8 TB/s[bwu-blog]3 TB/s[vr-page]
NVLink links per GPU18[nvlink-page]18[nvlink-page]18[nvlink-page]18[nvlink-page]36[nvlink-page]
PCIe (both directions)128 GB/s[bwu-blog]128 GB/s[h200-page]256 GB/s[bwu-blog]256 GB/s[bwu-blog]not disclosed[vr-page]
Max power700 W[h100-page]700 W[h200-page]1.2 kW[bwu-blog]1.4 kW[bwu-blog]not disclosed[vr-page]
Transistors80 billion[bwu-blog]80 billion[bwu-blog]208 billion[bw-arch]208 billion[bwu-blog]not disclosed[vr-page]

GB200 NVL72

 GB200 NVL72
NVLink-C2C (both directions)900 GB/s[gb200-blog]
Compute trays18[dgx-gb200-guide]
coolingliquid to cold plates on CPUs and GPUs; networking and storage air-cooled[dgx-gb200-guide]
CPUs36[gb200-page]
CPUs per tray2[dgx-gb200-guide]
Rack DC bus50 V[dgx-gb200-guide]
DPUs per tray2[dgx-gb200-guide]
GPUs72[gb200-page]
GPUs per tray4[dgx-gb200-guide]
HBM bandwidth, whole rack576 TB/s[gb200-page]
HBM, whole rack13.4 TB[gb200-page]
One NVLink link (both directions)100 GB/s[gb200-blog]
LPDDR5X bandwidth per Grace512 GB/s[gb200-page]
LPDDR5X per Grace480 GB[gb200-page]
Network per GPU400 Gb/s[dgx-gb200-guide]
Network cards per tray4[dgx-gb200-guide]
NVLink, whole rack130 TB/s[gb200-page]
NVLink ports per switch chip72[dgx-gb200-guide]
Power shelves8[dgx-gb200-guide]
Power supply rating5.5 kW[dgx-gb200-guide]
Power supplies per shelf6[dgx-gb200-guide]
Rack power120 kW[dgx-gb200-guide]
Input per power shelf33 kW[dgx-gb200-guide]
Switch chips per tray2[dgx-gb200-guide]
NVLink switch trays9[dgx-gb200-guide]
Switch tray, per direction57.6 Tb/s[dgx-gb200-guide]

GB300 NVL72

 GB300 NVL72
GPUs72[gb300-page]
HBM bandwidth, whole rack576 TB/s[gb300-page]
HBM, whole rack20 TB[gb300-page]
Network per GPU800 Gb/s[gb300-page]
NVLink, whole rack130 TB/s[gb300-page]
Rack powernot disclosed[gb300-page]

Vera Rubin NVL72 (preliminary)

 Vera Rubin NVL72preliminary
GPUs in the reference factory40,000[vr-page]
Reference factory power100 MW[vr-page]
GPUs72[vr-page]
HBM bandwidth, whole rack1,400 TB/s[vr-page]
HBM, whole rack20.7 TB[vr-page]
Coolant inlet45 °C[vr-page]
Network per GPU (both directions)450 GB/s[vr-page]
NVLink, whole rack216 TB/s[vr-page]
Rack powernot disclosed[vr-page]

DGX B200 (8-GPU node)

 DGX B200 (8-GPU node)
GPUs8[dgx-b200-page]
HBM bandwidth, whole rack64 TB/s[dgx-b200-page]
HBM, whole rack1.44 TB[dgx-b200-page]
Network per GPU400 Gb/s[dgx-b200-page]
System power14.3 kW[dgx-b200-page]
NVLink, whole rack14.4 TB/s[dgx-b200-page]
NVSwitch chips2[dgx-b200-page]
Rack units10[dgx-b200-page]

Scale-out switches

SwitchPortsOpticsAvailability
Quantum-2 (QM9700 class), InfiniBand NDR64[quantum2-page] × 400 Gb/spluggableproduct
Quantum-X800, InfiniBand XDR144[qx800-page] × 800 Gb/spluggableproduct
Spectrum-4 SN5600, Ethernet64[eth-switch-page] × 800 Gb/spluggableproduct
Quantum-X Photonics Q3450, InfiniBand (co-packaged optics)144[photonics-page] × 800 Gb/sco-packagedplannedcommercial availability planned for early 2026 (blog dated 2025-08-18)
Spectrum-X Photonics SN6810, Ethernet (co-packaged optics)128[cpo-blog] × 800 Gb/sco-packagedplannedavailable in the second half of 2026
Spectrum-X Photonics SN6800, Ethernet (co-packaged optics, four ASICs)512[cpo-blog] × 800 Gb/sco-packagedplannedavailable in the second half of 2026

DGX SuperPOD (GB200) design rules

Leaves per rail group8[superpod-network]
Largest design (SUs)16[superpod-network]
Switch ports (radix)64[quantum2-page]
Rails4[superpod-network]
Spines per rail group6[superpod-network]
Racks per scalable unit8[superpod-network]

Rack power delivery

 Rack power delivery
Rack DC bus today54 V[800v-blog]
Busbar copper, 1 MW at 54 V200 kg[800v-blog]
Planned rack feed800 V DC[800v-blog]
Planned rack power1 MW[800v-blog]
Energy storage per GPU65 J[smooth-blog]

Rack cooling

 Rack cooling
CDU approach5 K[water-blog]
One CDU's capacity2 MW[water-blog]
Cold plate rating4 kW[water-blog]
Rack power, hyperscale today135 kW[water-blog]
Rack power, earlier data centres20 kW[water-blog]
What the liquid coolsCPUs and GPUs on cold plates; networking and storage air-cooled[dgx-gb200-guide]

Physical properties

Water's specific heat is computed from NIST's Shomate equation at 298.15 K (chapter 7); air's from NASA's ratio of specific heats and gas constant.

Air density1.229 kg/m³[nasa-air]
Heat-capacity ratio of air1.4[nasa-gas]
Gas constant of air286 J/(kg K)[nasa-gas]
Water per litre1 kg (illustrative)[nist-water]

Other rack- and pod-scale designs

Google TPU v5p pod

 Google TPU v5p pod
Accelerators8,960[tpu-v5p]
BF16, dense459 TFLOP/s[tpu-v5p]
HBM bandwidth2.765 TB/s[tpu-v5p]
Scale-up per chip (both directions)1.2 TB/s[tpu-v5p]
Scale-up topology3D torus; 4x4x4 cubes joined by optical circuit switches[tpu-v5p]

Google TPU7x (Ironwood) pod

 Google TPU7x (Ironwood) pod
Accelerators9,216[tpu-7x]
BF16, dense2,310 TFLOP/s[tpu-7x]
HBM bandwidth7.38 TB/s[tpu-7x]
Scale-up per chip (both directions)1.2 TB/s[tpu-7x]
Scale-up topologynot disclosed[tpu-7x]

AMD Helios (72 x Instinct MI450) (planned)

 AMD Helios (72 x Instinct MI450)planned
Accelerators72[helios-blog]
HBM bandwidth19.6 TB/s[helios-blog]
HBM bandwidth, whole rack1,400 TB/s[helios-blog]
HBM capacity432 GB[helios-blog]
HBM, whole rack31 TB[helios-blog]
RackOpen Rack Wide (double-wide), liquid-cooled[helios-blog]
Scale-out, whole system43 TB/s[helios-blog]
Scale-up, whole system260 TB/s[helios-blog]
Scale-up topologynot disclosed[helios-blog]

AWS Trn2 UltraServer (64 x Trainium2)

 AWS Trn2 UltraServer (64 x Trainium2)
Accelerators64[trn2-page]
FP8, whole system83,200 TFLOP/s[trn2-page]
HBM bandwidth, whole rack185 TB/s[trn2-page]
Chips per instance16[trn2-page]
FP8 per instance20,800 TFLOP/s[trn2-page]
HBM bandwidth per instance46 TB/s[trn2-page]
Scale-out, whole system12.8 Tb/s[trn2-page]
Scale-up per chip (both directions)not disclosed[trn2-page]
Scale-up topologyNeuronLink across four 16-chip instances[trn2-page]

AWS Trainium3 UltraServer (144 x Trainium3)

 AWS Trainium3 UltraServer (144 x Trainium3)
Accelerators144[trainium-page]
HBM bandwidth4.9 TB/s[trainium-page]
HBM bandwidth, whole rack706 TB/s[trainium-page]
HBM capacity144 GB[trainium-page]
HBM, whole rack20.7 TB[trainium-page]
Scale-up per chip (both directions)not disclosed[trainium-page]
Scale-up topologyNeuronSwitch all-to-all fabric[trainium-page]

Llama 3 405B pre-training (chapter 9)

Days in the reliability record54[llama3]
Data-parallel replicas128[llama3]
GPUs16,384[llama3]
Pipeline stages16[llama3]
GPUs per NVLink server8[llama3]
Tensor parallel8[llama3]
Unexpected interruptions419[llama3]

Illustrative cost inputs (chapter 11)

Round numbers chosen for the picture, not prices or quotes:

Capital cost per rack (USD)3,500,000 (illustrative)
PUE (facility over IT power)1.2 (illustrative)
Electricity (USD per kWh)0.1 (illustrative)
Utilisation0.7 (illustrative)
Write-off period (years)4 (illustrative)

Quoted claims

Shown where relevant, attributed, and never used as model inputs:

Sources