MXH940 PCIe 4.0 x16 NTB Host Adapter

PCI Express Gen4 x16 NTB Host Adapter

The MXH940 PCI Express Gen4 NTB Host Adapter is our high performance optical clustering product. Based on Microchip® Gen4 PCI Express bridging architecture and Samtec PCIe Gen4 FireFly® optical engine, the MXH940 NTB host adapter provides advanced features for non-transparent bridging (NTB) over long distance PCIe. The adapter card supports the full Dolphin eXpressWare software stack.

  • One x16 PCIe edge port
  • Two x8/x4 PCIe optical cable ports
  • MPO patch cable
  • Low Profile Design
  • Dual MTP connectors
  • Non Transparent Bridging
  • 256 Gigabit/s performance
  • PIO and DMA RDMA
  • Full Dolphin Software Stack

Product Data

The MXH940 Gen4 PCI Express NTB Host Adapter is our high performance optical interface to external processor subsystems. Based on Microchip® Gen4 PCI Express bridging architecture and Samtec PCIe FireFly® optical engine, the MXH940 host adapter provides advanced features for non-transparent bridging (NTB) over long distance PCIe.

For high performance application developers, the MXH940 host adapter combines 256 Gbit/s performance with an application to application latency from 500 nanoseconds. Inter-processor communication benefits from the high throughput and low latency. Using the latest SmartIO technology software from Dolphin, applications can now access PCIe devices located in computers up to 100 metres way as if they was attached to the local system.

The MXH940 performs both Remote Direct Memory Access (RDMA) and Programmed IO (PIO) transfers, effectively supporting both large and small data packets. RDMA transfers result in efficient larger packet transfers and processor off-load. PIO transfers optimize small packet transfers at the lowest latency. The combination of RDMA and PIO creates a highly potent data transfer system.

Dolphin’s software suite takes advantage of PCI Express’ RDMA and PIO data transfer scheme. Delivering a complete deployment environment for customized and standardized applications. The suite includes a Shared-Memory Cluster Interconnect (SISCI) API as well as a TCP/IP driver and SuperSockets software. The SISCI API is a robust and powerful shared memory programming environment.

The optimized TCP/IP driver and SuperSockets™ software remove traditional networking bottlenecks, allowing standard IP and sockets applications to take advantage of the high performance PCI Express interconnect without modification. The overall framework is designed for rapid development of inter-processor communication systems.

The MXH940 card comes with a full license to the Dolphin eXpressWare software. The MXH942 Gen4 Adapter card does not include any software license and is well suited for high performance Transparent IO Expansion applications. The MXH940 card is fully supported in eXpressWare 5.19.2 and newer.

Supported topologies

Using the MXH940 card, you can connect two systems using PCIe Gen4 x4, x8 or x16 depending on the throughput requirements. You can also connect 3 systems using a x8 cable between each system or 5 systems using x4 cables.


The card is available in several variants with reduced number of FireFly optical modules mounted. The maximum performance and supported topologies for these cards will vary. Details can be found in the following table:

MXH94x NTB Host card variants
Part Number Installed FireFly devices Supported PCIe configuration Required MPO Patch Fiber Cable
MXH940 Two x8 x16, Two x8 Two 24 strand
MXH941 One x8 x8 One 24 strand
MXH943 Two x4 x8, Two x4 Two 12 strand
MXH944 One x4 x4 One 12 strand
MXH949 Four x4 x16, Two x8, Four x4 Four 12 strand


Fiber Patch Cables

The MXH94x cards are carefully designed for maximum cable length and supports fiber cables up to 100 meter optical cables. The x8 FireFly device configuration requires two MPO female, 24 strand, OM3 50/125, Key up - Key up (Type C) cables. The x4 FireFly device configuration requires two MPO female, 12 strand, OM3 50/125, Key up - Key up (Type B) cables.


  • PCI Express® 4.0 compliant - 16.0 GT/s per lane
  • Slot compliant with Gen1, Gen2 and Gen3 PCI Express
  • Samtec FireFly optical engine
  • MTP connectors
  • Four x4 Gen4 PCI Express cable ports that can be configured as:
    • One - x16 PCI Express port
    • Two - x8 PCI Express ports
    • Four - x4 PCI Express ports
  • Four NTB ports
  • RDMA support through PIO and DMA
  • Clock isolation support
  • Non-transparent bridging to cabled PCI Express systems
  • Low profile PCI Express form factor
  • Flash for custom system configuration
  • Link status LEDs through face plate
Feature Description
Link Speeds 64 Gbit/s per port, total 256 Gbit/s
Active Components Microchip / PFX Gen4 PCI Express Switch with DMA
Samtec FireFly PCI Gen 4.0
PCI Express®

Base Specification 4.0

Topologies Point to point, 3 or 5 node Mesh Topology
Cable Connections Dual x8 MPO connectors.
Fiber optic cable up to 100 meters
Power Consumption (Max)

12 Volt: 2.95 A
3.3 Volt: 0.84 A
3.3 VAUX: 0.35 A

Mechanical Dimensions Low profile, Half Length - 68.90 mm (2.731 inches) x 167.65 mm (6.600 inches)
Operating Environment Operating Temperature: 0°C - 55°C (32°F - 131°F), Air Flow: 700 LFM (Preliminary)
Relative Humidity: 5% - 95% (non- condensing)
Storage Environment Storage Temperature: -40°C - 70°C (-40°F - 158°F)
Relative Humidity 95% (non- condensing) at 35°C
Software SuperSockets™ Berkley Sockets API
Microsoft WinSock2/LSP support
Advanced TCP/IP driver
PCIe bracket

Full height plate mounted
Half height plate not included, only available for x8 and x4 configurations.

Configuration DIP-switch
NTB / safe boot
Regulatory Compliance CE Mark
FCC Class A
RoHS compliant
Operating Systems Windows
MXH84x NTB Host card variants
Part Number Installed FireFly devices
MXH940 Two x8
MXH941 One x8
MXH943 Two x4
MXH944 One x4
MXH949 Four x4

Dolphin eXpressWare software license included with all NTB variants.

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