The universal slot is an AGP thing. It can support 3.3v and 1.5v
From: Ingraham, Andrew [mailto:Andrew.Ingraham@compaq.com]
Sent: Wednesday, April 28, 1999 6:02 AM
To: Mailing List Recipients
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
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.