My jaw has hit the floor...

Greg Lindahl lindahl at
Thu Feb 15 09:17:42 PST 2001

On Wed, Feb 14, 2001 at 11:55:54PM -0500, Alan Grimes wrote:


Why did your jaw hit the floor? This is just a hyped press release
about a known technology, AMD's upcoming "Lightning Data Transport",
now renamed HypedTransport Technology (er, HyperTransport Technology).

The object is to have an intermediate bus in the middle of the chipset
which is capable of supporting connections between the chipset and
various I/O busses, like PCI and PCI-X. Today's chipsets are built in
a monolithic fashion, and so it's hard to add PCI-X to a chipset. If
LDT is in play, all you need to do is design a LDT-to-PCI-X chip, and
use it on any motherboard that has an LDT processor chipset.

The initial LDT runs at 6.4 gigabits per second, or only 800 megabytes
per second. That means it's not fast enough to run the memory
subsystem through it, but it is fast enough for PCI-X. Remember that
people are seeing actual throughput of 266 MB/s on today's PCI-4x
machines (Myrinet cards and ServerWorks chipsets.)

-- g

More information about the Beowulf mailing list