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RE: PCI Motherboard Conventions

Title: RE: PCI Motherboard Conventions

The universal slot is an AGP thing. It can support 3.3v and 1.5v

-----Original Message-----
From: Ingraham, Andrew [mailto:Andrew.Ingraham@compaq.com]
Sent: Wednesday, April 28, 1999 6:02 AM
To: Mailing List Recipients
Cc: 'pci-sig'
Subject: RE: PCI Motherboard Conventions

> Gabe Fitch asked:
>How many motherboard manufacturers have PCI slots that are keyed only
>for 3.3 V?

Very few today, but that may change soon.

>How many even supply 3.3 V to the PCI slot?

Some time ago, I heard estimates ranging from 20% to over 50%.  May be
higher now.

Revision 2.2 of the PCI Spec, released last December, requires 3.3V power at
all PCI slots.

>How many motherboard manufacturers have universal PCI slots?

There is no such thing as a universal PCI slot.  A slot is either 3.3V or 5V
(in terms of its signaling environment and keying), never both.  Only PCI
expansion cards can be universal.

>What is the industry trend? Are all PCI I/O cards supposed to be made

PCI revision 2.2 recommends that all new I/O cards be universal.  Those that
are not, are likely to suddenly find themselves out of a market when the
chipset/motherboard industry makes the move to 3.3V PCI buses.  I have seen
estimates that it will happen this year.

Andy Ingraham