I have a LSI Logic SCSI card that is PCIX and I only have PCI slots.

Can I use it?

It is this one.

From that link... I see

With PCI-X throughput of 1056 MBps, this adapter also capitalizes on maximum system performance for those systems needing it; yet is backward compatible with existing PCI systems.
So, I'm assuming yes, I can use it.

However, I tried to install it in one box and sure enough... right after I did... the box wouldn't boot.
Somehow the mobo died. Thankfully, it is under warranty and I should get the new mobo in the mail today.

What I don't understand... when they say backwards compatable:

I can use a PCIX card in a PCI slot?

or

I can use a PCI card in a PCIX slot?

or

Both?

I was reading up on the technical details of it @
http://www.pcisig.com/specifications/pcix_20/#overview

But... nothing really stands out to me. Then again... it is morning and I've yet to get my coffee.