PCIe Backwards Compatible?

[qz33]

Just real quick-

I know old PCI cards can be used with PCIe connectors but the speed will be old PCI speed.

Can PCIe cards be used with PCI connectors?  I doubt it.

[socrates]

no they cannot.

[socrates]

I should say a bit more.

The reason why is because the pci slot is too old of technology to recognize the pci-e card.  However, the pci-e slot is newer technology, and is therefore able to read the new and old technology (pci-e cards and pci cards). 

[Deerpark]

And to add to that.... as far as I know PCI-E is only compatible with PCI on the software level. You can't actually install a PCI card in a PCI-E slot.

[socrates]

And to add to that.... as far as I know PCI-E is only compatible with PCI on the software level. You can't actually install a PCI card in a PCI-E slot.

yes, I believe that's correct.

[qz33]

And to add to that.... as far as I know PCI-E is only compatible with PCI on the software level. You can't actually install a PCI card in a PCI-E slot.

yes, I believe that's correct.

If this is true then what purpose does PCI-E backwards compatability with old PCI cards serve?
How come this is listed as an advantage for PCI-E?  I thought old cards were still supposed to be useable with the new slots.

[socrates]

Good question.

[Deerpark]

The point is, if you have software that is purpose written to interface with a specific PCI card, you can change the card to an equivalent PCI-E card and the software will continue to function.
The average user will probably never be in a situation where this is an advantage but for enterprises this could potentially save them a lot of money. It will make it a lot more compelling to switch to PCI-E architecture if companies only have to change their hardware and not rewrite their software.