PCIe Express Pinouts Description for Single-
Slot Socket Direct Card
ConnectX-6 single-slot Socket Direct cards offer improved performance to dual-socket servers by
enabling direct access from each CPU in a dual-socket server to the network through its dedicated
PCIe interface. The PCIe x16 interface is split into two PCIe x8 in a row, such that each of the PCIe x8
lanes can be connected to a dedicated CPU in a dual-socket server. In such a configuration, Socket
Direct brings lower latency and lower CPU utilization as the direct connection from each CPU to the
network means the Interconnect can bypass a QPI (UPI) and the other CPU, optimizing performance
and improving latency. CPU utilization is improved as each CPU handles only its own traffic and not
traffic from the other CPU.
In order to allow this capability, a system with a special PCI Express x16 slot is required. Table 31
provides the pin definitions of the required four special PCIe pins.
P
CI
e
p
in
#
Server Connection for 2x PCIe x8 mode Server
Connection for
1x PCIe x16
mode
Comments
B82 1Kohm pull up to 3.3VAUX Either leave
unconnected or
pulled to GND
Configure the card to work
at 2x PCIe x8 or 1x PCIe x16
modes
A32 P signal of differential PCIe clock (100MHz nominally)
of the CPU which connects to PCIe lanes 15-8 of the
PCIe connector
Not Connected
PCIe clock for ConnectX-6
PCIe bus lanes [15:8]
A33 N signal of differential PCIe clock (100MHz nominally)
of the CPU which connects to PCIe lanes 15-8 of the
PCIe connector
Not Connected
A50 PERST signal from the CPU which connects to PCIe
lanes 15-8 of the PCIe connector
Not Connected PERST (PCIe Reset) for
ConnectX-6 PCIe bus lanes
[15:8]
This section applies to ConnectX-6 single-slot cards (MCX653105A-EFAT and MCX653106A-
EFAT).
To Next Page
Loading...
