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everettstudi

join:2000-11-22
Phoenix, AZ

PCIe

How can I identify if I have PCI or PCIe?
Can one buy an adapter card from PCI to PCIe?

Thank you,
Everett


koitsu
Premium,MVM
join:2002-07-16
Mountain View, CA
kudos:23

1 recommendation

Pictures on these pages should help:

PCI: »en.wikipedia.org/wiki/Conventional_PCI
PCIe: »en.wikipedia.org/wiki/PCI_Express

Please note that PCIe (PCI Express) is not the same thing as PCI-X. Don't confuse the two.

As for an adapter: absolutely not. They are in no way shape or form backwards compatible.
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.


FizzyMyNizzy

join:2004-05-29
New York, NY

2 edits
reply to everettstudi
»www.google.com/products/catalog?···oring=tp

StarTech.com PCI to PCI Express Adapter Card PCIe x1 to PCI slot adapter



StarTech PCI to PCI Express Adapter Card Model PCI1PEX1
»www.newegg.com/Product/Product.a···15158190

StarTech PCI-X to x4 PCI Express Adapter Card Model PCIX1PEX4
»www.newegg.com/Product/Product.a···15158315



Please read the requirements before getting one.


koitsu
Premium,MVM
join:2002-07-16
Mountain View, CA
kudos:23

1 recommendation

Key point: I've no problem admitting I'm wrong: I had no idea such adapters existed. Thanks, FizzyMyNizzy See Profile!

That said, both products (the PCI-to-PCIe x1 adapter and the PCI-X to PCIe x4 adapter) are downright scary. I cannot even begin to imagine how these can work correctly, especially considering things like PCI Express requires MSI (see first line of "MSI types"). With PCI and PCI-X MSI/MSI-X is optional.

So what happens when you shove a PCIe NIC that makes heavy use of MSI (and most do -- in fact, the well-known-as-reliable Intel NICs are one such example) in that adapter? This gets me wondering... let's see...

For the first adapter, it seems its driven by a PI7C9X111SL controller bridge. It's not shown in the picture, which means it's probably on the rear/back of the card. Sadly Pericom's site returns HTTP 403 for the controller itself. I did find a Flash file (don't ask) on a Russian site that has a 1-page PDF brief of the PI7C9X111SL, and it does support INT-level triggering and MSI as well.

For the 2nd adapter, the PDF user manual mentions use of the PLX PEX8114 controller bridge. PLX's documentation does state that they support MSI (and thus I assume MSI-X), and I think that's doable since there's a controller bridge involved (i.e. there is actual logic/possibly microcode that can handle MSI-to-no-MSI conversions).

If you ask me, I would trust a PCI --> PCIe adapter (e.g. "this adapter lets you use a PCI card in a PCIe slot") more than a PCIe --> PCI adapter. The above bridges support EITHER MODEL (meaning you can find other StarTech-brand adapters that let you convert the opposite direction), but my point is that there is a "middle-man" chip in between to make everything work. I can only imagine what these things show up as on the PCI and PCIe bus, what their BARs and capabilities look like, etc... I tend to stay away from such converters.
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.


koitsu
Premium,MVM
join:2002-07-16
Mountain View, CA
kudos:23

1 recommendation

BTW, these adapters remind me of something I put together in Photoshop back in 2002:

»jdc.koitsu.org/lj/crazy_card.jpg

Seems I should update that to support PCIe......
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.

JoelC707
Premium
join:2002-07-09
Lanett, AL
kudos:5

1 recommendation

reply to koitsu
Click for full size
I know servers have had adapters for years now. The Dell 2950's I have can support PCI-X or PCIe expansion slots. The base port on the motherboard is PCIe and the riser board plugs into that. Also I discovered the Broadcom NICs onboard are actually PCI-X variants and use a bridge chip to convert to PCIe x4 (one for each NIC IIRC).

Additionally some expansion cards have embedded PCIe to PCI-X bridge chips. The Dell PERC 5 card is one such animal (the PERC 6 eliminated that conversion/bottleneck. Also the original OCZ RevoDrive PCIe SSD used a PCI-X bridge. Their reason was that the RAID controller chip they sourced was MUCH cheaper in PCI-X variant than PCIe so they opted for those chips + a bridge chip.

All that said, there is a BIG difference between an expansion card or server based bridge chip that's intended to do that bridging than one of those StarTech cards. In the StarTech case you have to hope they did all the conversions correctly and you can only use half-height cards. The others are intended for the application and were designed so from the start.

Still, it's nice to know such animals exist in the event they are needed in a pinch (not sure I'd use one long term but who knows). See attached screenshot for what the bridge devices on a Dell 2950 show up as. Most appear to be Intel chips. If you want screenshots from any of the device details screens (hardware IDs and such) let me know and I'll be glad to get them for you.


dbarber

join:2000-07-25
West Chester, PA
reply to koitsu
said by koitsu:

BTW, these adapters remind me of something I put together in Photoshop back in 2002:

Now THAT looks scary! Kinda funny too!
--
These opinions are strictly my own. However, if you really want them, we can negotiate.


Cthen

join:2004-08-01
Detroit, MI
Reviews:
·Verizon Wireless..
reply to FizzyMyNizzy
said by FizzyMyNizzy:

Please read the requirements before getting one.

Also see if you can find one under a better brand name. StarTech has a bad reputation of their products failing for the most simple reasons. Mostly bad drivers that they never fix but still, do you want to chance that?
--
"I like to refer to myself as an Adult Film Efficienato." - Stuart Bondek