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Silver 4U rackmount server chassis, front drive bays and ventilation grille visible

Supermicro

Supermicro SYS-421GU-TNXR 4U barebone server

SKU CH-7W2B-CGMGM MPN SYS-421GU-TNXR

4U rackmount barebone for AI and HPC workloads, supporting dual Xeon CPUs, 32 DDR5 DIMM slots up to 8 TB, and four double-width GPUs with NVLink

  • ProcessorIntel Xeon
  • Graphics processorMax GPU Count: Up to 4 double-width GPU(s) Supported GPU: NV
  • Installed RAMNo Memory Installed
  • Form factor4U Rackmount
  • Processor socketLGA 4677
  • Target workloadAI/ML/HPC
  • 32 DDR5 slots support up to 8 TB for large datasets
  • Dual Xeon sockets accept up to 350 W TDP for heavy compute
  • Four double-width GPUs with NVLink accelerate AI training
  • Eight PCIe 5.0 x16 slots enable high-bandwidth expansion
  • 10 GbE LAN and M.2 boot drives simplify deployment

4U AI barebone for dual Xeon

The Supermicro SYS-421GU-TNXR is a 4U rackmount barebone designed for AI, machine learning and high-performance compute workloads. It accepts up to two 4th Generation Intel Xeon Scalable processors with future support for 5th Generation parts. Each socket handles up to 350 W TDP using air or liquid cooling. The Intel C741 chipset provides the platform foundation.

Verify CPU cooler clearance and power budget

Before ordering, confirm that your chosen LGA 4677 processors do not exceed the 350 W TDP limit per socket. Ensure the cooling solution you select fits the 4U form factor and matches the air or liquid specification. The system ships with no CPU or memory installed, so you must source compatible DDR5 4800 ECC modules and processors separately. Network connectivity relies on the integrated Intel X710-AT2 dual-port 10 Gigabit controller.

Four double-width GPU slots with NVLink

The chassis supports up to four double-width GPUs including NVIDIA HGX H100 80 GB SXM modules linked by NVLink. CPU-to-GPU communication runs over PCIe 5.0 x16. Eight PCIe 5.0 x16 slots provide additional expansion. Storage options include six 2.5-inch hot-swap bays for NVMe, SATA or SAS drives and two M.2 slots configurable for NVMe or SATA boot devices. No drives are included.

How it compares

Measured against everything we stock in Barebone Servers & DIY Kits, at today’s prices. Recalculated every night.

Price $8,183.99
Pricier than about 84% of the 532 comparable items (median $2,503.49).

New to this? Buying server hardware with crypto — what to check, what it costs to pay, and what is never asked for.

Specifications

Product
Brand nameSUPERMICRO
Model nameSYS-421GU-TNXR
Target workloadAI/ML/HPC
Processor
ProcessorIntel Xeon
Processor socketLGA 4677
Preinstalled processorNo CPU Installed
Max supported CPUs2
ChipsetIntel C741
Memory
Installed RAMNo Memory Installed
RAM slots32 × 288Pin
Maximum supported memoryUp to 8 TB: 32 × 256 GB DRAM
Supported memoryDDR5 4800
ECC supportYes
Storage
Preinstalled storageNo Storage Installed
M.2 slots2 x M.2 NVMe OR 2 x M.2 SATA3
Hot-swap drive bays6 × 2.5 in hot-swap NVMe/SATA drive bays (6 × 2.5 in NVMe hybrid)
Connectivity
Primary LAN controllerIntel X710-AT2
Top LAN speed10 Gigabit
Ports & slots
PCIe slots1 x PCIe 5.0 x16 LP slot(s)
7 x PCIe 5.0 X16 slot(s)
VGA ports1
Ethernet port2
Power
Power supply4x 3000 W Redundant Titanium Level power supplies
Size & build
Form factor4U Rackmount
Product dimensions7 in × 17.67 in × 32.79 in
Product weight105 lb (47.6 kg)
Shipping weight63.50 kg
Package size1260 × 700 × 370 mm
Environment & compliance
Temperature rangeOperating Temperature: 10 °C to 35 °C (50 °F to 95 °F)
Non-operating Temperature: -40 °C to 60 °C (-40 °F to 140 °F)
Humidity rangeOperating Relative Humidity: 8% to 90% (non-condensing)
Non-operating Relative Humidity: 5% to 95% (non-condensing)

Questions about this item

Does the SYS-421GU-TNXR include any CPUs, memory modules or drives, or must I source them separately?

The barebone arrives with no CPU installed, no memory installed and no storage installed; you must add up to two LGA 4677 Xeon processors, DDR5 4800 ECC DIMMs and your choice of 2.5" NVMe, SATA or SAS drives plus M.2 boot devices.

Which DDR5 4800 capacity should I choose to reach the 8 TB maximum across the 32 slots?

Populate all 32 slots with 256 GB ECC DDR5 4800 modules to hit the 8 TB ceiling; smaller capacities work but will leave total memory below the maximum.

What does the PCIe 5.0 x16 CPU-to-GPU interconnect mean for an HGX H100 4-GPU (80 GB) configuration?

Each of the four double-width GPUs connects to the CPUs through a dedicated PCIe 5.0 x16 link, while the GPUs talk to each other over NVIDIA NVLink for high-bandwidth peer transfers.

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