Sun Fire[TM] Servers: Differences Between PCI-X and PCI Express I/O Technologies

Asset ID:	1-71-1003507.1
Update Date:	2009-12-04
Keywords:

Solution Type Technical Instruction Sure

Solution 1003507.1 : Sun Fire[TM] Servers: Differences Between PCI-X and PCI Express I/O Technologies

Related Items


Sun Ultra 5 Workstation
 Sun Blade 2000 Workstation
 Sun Blade 2500 Workstation
 Sun Fire V240 Server
 Sun Fire V250 Server
 Sun Fire V440 Server
 Sun Fire V480 Server
 Sun Fire V60x Server
 Sun Fire V65x Server
 Sun Fire E25K Server
 Sun Enterprise 450 Server
 Sun Fire V20z Compute Grid Rack System
 Sun Ultra 450 Workstation
 Sun Fire E20K Server
 Sun Blade 100 Workstation
 Sun Blade 150 Workstation
 Sun Ultra 30 Workstation
 Sun Ultra 80 Workstation
 Sun Fire V880z Visualization Server
 Sun Enterprise 3500 Server
 Sun Fire V210 Server
 Sun Fire V890 Server
 Sun Fire 12K Server
 Sun Enterprise 220R Server
 Sun Fire V20z Server
 Sun Fire V880 Server
 Sun Enterprise 250 Server
 Sun Blade 1500 Workstation
 Sun Fire V40z Server
 Sun Fire 15K Server
 Sun Fire V60x Compute Grid Rack System
 Sun Blade 1000 Workstation
 Sun Ultra 10 Workstation
 Sun Ultra 60 Workstation
 Sun Fire V490 Server
 Sun Enterprise 420R Server

Related Categories


GCS>Sun Microsystems>Servers>x64 Servers

PreviouslyPublishedAs
204930

Description
This document discusses the differences between PCI-X and PCI Express I/O
technologies. Sun currently ships PCI and PCI-X based systems and, in the
near future, will be shipping PCI Express based systems.

Steps to Follow
PCI, PCI-X and PCI Express are industry-standard I/O technologies.

PCI supports 33MHz, 66MHz clock speeds and operates in 64/32bit mode. PCI
supports 5V as well as 3.3 volt signaling.
PCI-X supports 66MHz, 133MHz, 266MHz, and 533MHz clock speeds and is 64-bits
wide. PCI-X 66MHz, 133MHz, 266MHz and 533MHz clock speeds provide the following throughput respectively: 4Gbit/sec, 8Gbit/sec, 17Gbit/sec, 34Gbit/sec. PCI-X cards are backward compatible to the "old regular" PCI-based systems. PCI-X supports only 3.3 volt signaling. Due to this, PCI-X adapter cards are only backward compatible with previous generation 3.3V PCI systems.
PCI Express is a serial interconnect, point-to-point link, not a parallel multidrop bus as is PCI/PCI-X. PCI Express can run on many lanes: x1,x2, x4,x8, and x16. Each lane gives 250Mbit/sec in single direction and 500Mbit/sec in duplex mode. The x16 lane gives 16Gbyte/sec(128Gbit/sec) throughput. PCI express is similar to Infiniband; they both have serial interconnects and can be used for interconnecting servers and clustering.
PCI-X is a shared bus. For example, all the devices on the bus share a single set of data lines and signal lines. PCI-Express is a switched bus, which should allow much more efficient use of the bandwidth between the devices and the system bus.
Physically, PCI-X and PCI Express are very different. PCI Express requires a different hardware connection, causing old PCI cards not to work in PCI Express slots. But from software perspective or from a driver/writers perspective they are identical, which is what makes PCI Express so
attractive. This allows companies to re-use the PCI-X/PCI software for PCI Express.

Product
Sun Fire E25K Server
Sun Fire E20K Server
Sun Fire 15K Server
Sun Fire 12K Server

Internal Comments
Audited/updated 12/03/09 Silvana.Villamil@SUN.com, Entry Level SPARC Content Team Member

PCI, PCI-X, PCI Express
Previously Published As
77128

Change History
Date: 2004-07-28
User Name: C149439
Action: Approved
Comment: Added product trademark. Corrected measurement abbreviations. Edited text.
Gail Waldron
Version: 2
Date: 2004-07-27
User Name: C149439
Action: Accept
Comment:
Version: 0

Attachments

This solution has no attachment