What is the switching capacity of the Dell Z9864F-ON vs NVIDIA Quantum-X800?

The Dell Z9864F-ON delivers 102.4 Tbps full duplex (51.2 Tbps non-blocking) with 64 ports of 800GbE. The NVIDIA Quantum-X800 Q3400-RA delivers 115.2 Tbps non-blocking with 144 ports of 800Gb/s.

Does InfiniBand or Ethernet perform better for AI training?

InfiniBand provides native in-network computing via SHARP offloads (up to 9X performance boost). Ethernet with RoCEv2 and Enterprise SONiC provides a standardized, vendor-agnostic path. InfiniBand leads for peak training efficiency; Ethernet leads for enterprise flexibility.

What is Co-Packaged Optics (CPO)?

CPO integrates silicon photonics directly with the switch ASIC, reducing electrical path length to millimeters. This improves signal integrity by 63X and reduces insertion loss from 22 dB to 4 dB.

Technical Assessment

800GbE Ethernet vs. NDR InfiniBand for Generative AI Fabrics

Dell PowerSwitch Z9864F-ON vs. NVIDIA Quantum-X800 — which fabric architecture is right for your trillion-parameter AI cluster?

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800G

Speed Tier

115.2 Tb/s

Max Throughput

10,368

Max NIC Scale

SHARP Offload Boost

Head-to-Head

Hardware Capacity Comparison

Switch radix directly dictates hop count and job locality. Reducing hops is essential for minimizing tail latency in fat-tree topologies.

Metric	Dell Z9864F-ON	NVIDIA Quantum-X800
Switching Capacity	102.4 Tbps full duplex / 51.2 Tbps non-blocking	115.2 Tbps non-blocking
Port Radix	64 x 800GbE (OSFP112)	144 x 800Gb/s (72 OSFP)
Packet Buffer	165.2 MB (deep buffer)	Ultra-low (cut-through)
Control Plane	Intel Xeon D-1714 (4C @ 2.3GHz)	Intel i3-8100H (4C @ 3.0GHz)
In-Network Compute	Cognitive Routing, RoCEv2	SHARPv4 (FP8, 9X boost)
Cooling	Air-cooled (45°C)	Air (Q3400) / 85% Liquid (Q3450)
Form Factor	2U	4U
Max Scale	8,000 GPU nodes	10,368 NICs
NOS	Enterprise SONiC (open)	NVOS + UFM (integrated)

Dell PowerSwitch Z9864F-ON

The Open Ethernet Approach

165 MB

Deep packet buffer absorbs incast during gradient synchronization

320

100GbE breakout ports for brownfield flexibility

5nm

Monolithic die for max efficiency in air-cooled 45°C environments

SONiC

Open-source NOS — no vendor lock-in, Linux-native management

Hardens Ethernet for lossless AI transport via RoCEv2, PFC, ETS, and DCBX. Cognitive Routing dynamically balances loads. Ideal for multi-tenant clouds and NVMe/TCP storage integration.

View Z9864F-ON Also: Z9664F-ON (400G)

NVIDIA Quantum-X800

The InfiniBand Approach

SHARPv4 offloads collective math ops directly in switch silicon

10,368

800Gb/s NICs in a single two-tier fat-tree topology

FP8

Native precision support for ReduceScatter & ScatterGather

4 dB

CPO insertion loss (vs. 22 dB pluggable) — 63X signal integrity

Credit-based flow control ensures naturally lossless transport. Self-healing technology and telemetry-based congestion control provide nearly 100% effective bandwidth with performance isolation.

View Q3400-RA Also: Q3401-RD

Need help choosing the right AI fabric?

Our networking specialists will help you evaluate both platforms for your specific workload and facility.

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Physical Engineering

Co-Packaged Optics & Cooling

As port densities hit 800G, traditional pluggable transceivers become a liability. NVIDIA's Q3450-LD integrates silicon photonics directly with the ASIC (CPO), but requires 85% liquid cooling.

Dell's Z9864F-ON uses a monolithic 5nm die optimized for standard air-cooled data centers up to 45°C — the pragmatic choice when liquid cooling infrastructure isn't available.

63X

Signal integrity (CPO)

4 dB

Insertion loss

45°C

Air-cooled (Dell)

Strategic Recommendation