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Flopper.io System Specification Sheet

HPE ProLiant Compute XD685 (Instinct MI355X)

8x Instinct MI355X CDNA 4 rack 2025

Overview

40.3
FP8 PFLOPS Dense
2.3 TB
Aggregate Memory
64.0 TB/s
Aggregate Bandwidth
Aggregate Power

Performance Metrics

PrecisionPeak (PFLOPS)Per GPU (TFLOPS)TFLOPS/W
FP640.678.6
FP321.3157.3
FP1620.12516.6
BF1620.12516.6
FP840.35033.2
FP480.510066.3
INT840.35033.2
FP680.510066.3

All figures are dense. Vendors commonly headline the sparse number, which is twice the dense one.

Configuration

Accelerator
Instinct MI355X OAM
Count
8
Memory per GPU
288 GB
Bandwidth per GPU
8.0 TB/s

Power & Efficiency

Aggregate Power
TDP per GPU
1400 W
FP8 Efficiency
Aggregate Bandwidth
64.0 TB/s

System Details

Vendor: HPE
Family: ProLiant Compute XD
Architecture: CDNA 4
Form Factor: rack
Release Year: 2025
Process Node: 3nm/6nm

Interconnect

4th Gen AMD Infinity Fabric across the eight-OAM OCP baseboard; 4x FHHL PCIe Gen5 x16 slots for fabric, NIC or DPU

Notes

The eight-way XD685 in its AMD Instinct MI355X configuration, liquid cooled, with accelerator kit S6J64A. This is an all-AMD machine, pairing eight MI355X OAM modules with two fifth-generation AMD EPYC processors. No chassis part number is recorded: HPE names the accelerator kit but never states which chassis it requires, and the two candidates differ. Compute comes from AMD's eight-GPU Instinct platform, where the sparse figures cover only the four datatypes AMD publishes them for, being FP8, FP16, BF16 and INT8; AMD gives no structured-sparsity figure for MXFP4 or MXFP6. HPE publishes no system power draw for the XD685, only twelve 3,000 W Titanium supplies, so nothing is summed.