PCI X backwards compat PCI?

[phishphreek]

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.

[HTRegz]

Hey Hey,

I've always understood it that PCI will work with a PCI-X slot but not the otherway around. Based on the quote you posted that makes sense and this (from your link) adds to the thought.

Migration to PCI-X 266 and PCI-X 533 is further simplified by retaining hardware and software compatibility with previous generations of PCI and PCI-X. As a result, new designs can immediately connect with hundreds of PCI and PCI-X products that are currently available. The combination of backwards compatibility and ease of migration provides investment protection for customers, developers, and manufacturers of existing PCI and PCI-X technologies as they migrate to PCI-X 266 and PCI-X 533.

The connector on the board is just a data bus right, it connects the device in. A standard PCI bus can carry at 66 and 133, the new spec is for 266 and 533. A PCI-X Card (depending on if it's 266 or 533 will be sending at those speeds, so the older PCI slot won't understand movement that fast).

It's sort of like a speed limit, driving below the speed limit is ok but if you start driving above the speed limit then you're looking for trouble.

Peace,
HT

[phishphreek]

HTRegz: Thanks for the reply. I understand clock rates and the bus. I was just a bit thrown on the following:

PCI Bus 64-bit, 133 MHz PCI-X backward compatible with PCI
PCI Modes Bus master DMA
PCI Data Burst Transfer Rate PCI 32-bit bus
@ 33 MHz 132 MB/s
PCI 64-bit bus
@ 33 MHz 264 MB/s
PCI 64-bit bus
@ 66 MHz 528 MB/s
PCI-X 64-bit bus
@ 100 MHz 800 MB/s
PCI-X 64-bit bus
@ 133 MHz

Why would they have this for a PCIX card if it won't work in a standard PCI slot?

Ok, I just called their tech support. They WILL work in a normal PCI slot... HOWEVER, you normally have to flash a new firmware image onto them. The don't recommend using it in a normal PCI slot becuase of the loss in performance.

If you're just using it specifically for data transfer (like backup/storage solutions) you will want the added speeds.

[Tim_axe]

A PCI-X bus is compatible with a PCI card. But this just means the PCI-X bus would run at regular PCI spec, and lose performance.

A PCI-X card should not fry in a PCI bus, unless their signaling voltages are different. If that was the case the card wouldn't fit. So I'm not sure how your motherboard got screwed up (concidence?)...but fortunately you can get it replaced...

[phishphreek]

Well... thats two mobos now that have been destroyed.

I convinced Dell that the video card is bad and screwing up the mobo and they are sending me a new video card, mobo and processor. Last time I try that. And I even read the technical specifications BEFORE I just started plugging in parts.

My Boss says: "Remember when you were a kid and you had all those toys? You were one of the kids that tried to put the triangle block in the circle hole with the hammer... weren't you?"

I swear I researched and thought I understood it.
So, I've come to the conclusion that the Dell Dimension 8400 sucks ass.

[The Duck]

All dells suck ass IMO, the company makes their computers specialized and small and jammed packed on purpose, because they want to make it a bitch to upgrade... It wasn't to long ago that someone posted about their dell having a microATX with no agp slot, and I think something was up with the cpu as well... I'v even heard that Dell uses specialized ram modules in some cases, though I can't confirm that...

My point is how is anyone supposed to upgrade that thing?? Dell obviously wasn't looking for the buyers best interest, because in monthes that thing will be obsolete and he won't be able to upgrade that thing...

I guess you can tell I hate dell with a passion, my dad got a dell and since then I have been given the pleasureable duty of fixing it whenever it decides not to work...

Ok i'll stop rambling now, back to the main topic ...