Intel® Server Board S3420GP TPS Functional
Architecture
Revision 2.4
Intel order number E65697-010
25
PCI Express* Interface
PCI Interface
SATA Interface
USB Host Interface
SMBus Host Interface
SPI Interface
LPC interface to IBMC
JTAG interface
LAN interface
ACPI interface
3.4
I/O Sub-system
Intel
®
3420 Chipset PCH provides extensive I/O support.
3.4.1
PCI Express Interface
Two different PCI-E configurations on single board are dependent on different board SKUs:
Intel
®
Server Board S3420GPLX
One PCI-E X16 slot connected to the PCI-E ports of CPU. Two PCI-E x8 slots and one SAS
module connected to PCI-E ports of PCIe switch. One PCI-E X8 slot and one PCI-E x4 slot
connected to the PCI-E ports of PCH.
Intel
®
Server Board S3420GPLC
One PCI-E X16 slot and one PCI-E X8 slot connected to the PCI-E ports of CPU. One PCI-
E x8 slot connected to the PCI-E ports of PCH.
Intel
®
Server Board S3420GPV
One PCI-E X16 slot and one PCI-E X8 slot connected to the PCI-E ports of CPU. One PCI-
E x8 slot connected to the PCI-E ports of PCH.
There is one 32-bit, 33-MHz, 3.3-V/5-V PCI slot.
Compatibility with the PCI addressing model is maintained to ensure all existing applications
and drivers operate unchanged.
The PCI Express* configuration uses standard mechanisms as defined in the PCI Plug-and-
Play specification. The initial recovered clock speed of 1.25 GHz results in 2.5 Gb/s/direction,
which provides a 250-MB/s communications channel in each direction (500 MB/s total). This is
close to twice the data rate of classic PCI. The fact that 8b/10b encoding is used accounts for
the 250 MB/s where quick calculations would imply 300 MB/s. The external graphics ports
support 5.0 GT/s speed as well. Operating at 5.0 GT/s results in twice as much bandwidth per
lane as compared to 2.5 GT/s operation.
When operating with two PCI Express* controllers, each controller can operate at either 2.5
GT/s or 5.0 GT/s. The PCI Express* architecture is specified in three layers: Transaction Layer,
Data Link Layer, and Physical Layer. The partitioning in the component is not necessarily along
these same boundaries.
