MXH916 PCIe 4.0 NTB Host Adapter

PCIe 4.0 x8 / x16 NTB Host Adapter

The MXH916 PCIe 4.0 NTB Host Adapter is our medium performance scale out solution. It has a x8 PCIe edge connector and a quad x4 SFF-8644 PCIe cable connector and supports a single x8 PCIe connection to one remote host or two x8 PCIe connections to two remote hosts.. The adapter card supports the full Dolphin eXpressWare software stack.

  • One x8 PCIe 4.0 edge port
  • Four x4 PCIe 4.0 Cable ports
  • Copper and fiber cables
  • 0.5 microsecond host to host latency
  • Low Profile Design
  • Quad SFF-8644 Connector
  • Non Transparent Bridging
  • 128 Gbit/s Performance
  • Full Dolphin Software Stack
Scale out PCI Express with the MXS924

Product Data

The MXH916 PCIe 4.0 NTB Host Adapter is our medium performance clustering product. Based on Microchip Switchtec® Gen4 PCI Express bridging architecture, the MXH916 host adapter includes advanced features for non-transparent bridging (NTB) and clock isolation.

For high performance application developers, the MXH916 host adapter combines 128 Gbit/s performance with an application to application latency below 500 nanoseconds. Inter-processor communication benefits from the high throughput and low latency. Using the latest SmartIO technology software from Dolphin, GPU / Cuda applications can now stream data to remote GPUs at at the same speed as to local GPUs. Advanced DMA features enables fast data transfers hosts.

Dolphin eXpressWare

The MXH916 card comes with a full license to the Dolphin eXpressWare clustering software. This includes

  • SISCI API - a robust and powerful shared memory programming environment for PCIe
  • Standard TCP/IP drivers
  • SuperSockets socket accelerator software
  • SmartIO - access to remote PCIe devices over PCIe
  • Board management software

Dolphin’s software suite takes advantage of DMA and PIO data transfer scheme to effectively supporting both large and small data transfers. PIO transfers optimize small packet transfers at the lowest latency. DMA moves data with virtually no CPU consumption. The eXpressWare software is currently available for Linux, Windows and VxWorks.

The overall software framework is designed for rapid development and deployment of inter-processor communication systems. More information about Dolphin eXpressWare clustering software.


The MXH916 card has a quad SFF-8644 cable connector and supports PCIe 4.0 cables. The MXH916 is carefully designed for maximum cable lengths. Fiber optics extends this distance to 100 meters. More info on cable alternatives for the MXH916 card.


The MXH916 can be used to create several types of PCIe networks:

  • A two node network can be realized using 2 cables (x8). Full PCIe Gen4 x8 performance between the two systems.
  • A three node network can be realized using 2 cables (x8) between each system. Full PCIe 4.0 x8 performance between the three systems.
  • A five node network can be realized using 1 cable (x4) between each system. Full PCIe 4.0 x4 performance between the five systems
  • Larger configurations can be realized with one or more of the MXS924 24 port PCIe 4.0 switch.

Transparent PCIe

In combination with Dolphins eXpressWare, the MXH916 supports surprise hot add when connected to a traditional external IO system. More on Dolphins Hot Add. If you don't need Transparent Hot Add, please select the Transparent MXH917 PCIe 4.0Adapter card.


  • PCI Express® 4.0 compliant - 16.0 GT/s per lane
  • Link compliant with Gen1, Gen2, Gen3 PCI Express
  • PCI Express 4.0 cables
  • Quad x4 SFF-8644 PCI Express 4.0 NTB cable ports that can be configured as:
    • One - x16 PCI Express port
    • Two - x8 PCI Express ports
    • Four - x4 PCI Express ports
  • RDMA support through DMA, PIO and System DMA
  • Copper and fiber-optic cable connectors
  • Full host Clock isolation support. Automatic support for host running CFC or SSC
  • Non-transparent bridging to cabled PCI Express systems
  • Low profile PCI Express form factor
  • EEPROM for custom system configuration
  • Link status LEDs through face plate

Dolphin PCIe 4.0 NTB Host Adapter comparison

The table below compares the PCIe 4.0 NTB host adapters available from Dolphin.

Adapter PCIe 4.0 Edge PCIe 4.0 Cable port
MXH930 x16 Quad x4 SFF-8644
MXH918 x8 Dual x4 SFF-8644
MXH916 x8 Quad x4 SFF-8644
MXH914 x8 Single x4 SFF-8644


Feature Description
Link Speeds 64 Gbit/s per port, total 128 Gbit/s
Application Performance Less than 500 nanosecond latency (application to application)
Active Components Microchip Switchtec® Gen4 PCI Express Switch
PCI Express®

Base Specification 4.0
Card Electromechanical Specification 3.0
External Cabling Specification Spec 4.0


2 node direct cable
3 - 5 node mesh topology
Switch topologies using MXS924

Cable Port Quad SFF-8644 / Four x4 Gen4 Ports
Supported cables

PCIe 4.0 cables
PCIe fiber optic cable

Maximum power rating

12 Volt: max 1.66A (no port power) 2.86A (max port power)
+3.3 Volt: Not connected
+3.3 Volt Aux: max 100mA

Typical power rating

12 Volt: 1.5 A (no port power)
+3.3 Volt: Not connected
+3.3 Volt Aux: max 100mA

Port power supply (per cable port)

VPWR: 3.2V - 3.4V, 0.86A
VMGTPWR: 3.2V - 3.4V, 0.89mA

Mechanical Dimensions Low profile, Half length 167.65mm- (6.6 inches) x 68.90 mm (2.731 inches)
Operating Environment Operating Temperature: 0°C - 55°C (32°F - 131°F)
Airflow : 350 LFM (preliminary)
Relative Humidity: 5% - 95% (non- condensing)
Software SuperSockets™ Berkley Sockets API
Microsoft WinSock2/LSP support
TCP/IP driver
Multicast groups Max 16, default 4
Configuration DIP-Switch
Regulatory approvals

CE Mark
FCC Class A
RoHS compliant
UL94V-0 compliant

Regulatory EMC tests

EN 55032:2012
EN 55035:2017
EN 61000-3-2:2014
EN 61000-3-3:2013
47 CFR Part 15, Subpart B (Clause 15.107 and 15.109) in conjunction with ANSI C63.4:2014
CISPR 35:2016 Edition 1.0 (CISPR/I/412/CDV) Korean Harmonized standard, KN 35

Operating Systems


MXH916 - NTB Host + Dolphin eXpressWare software license

MXH917 - Transparent Host

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