The X is NOT for Express!

April 29, 2008 2:06 PM

Is there such thing as a PCI-X video card that will work in a Mac G5 tower?

We need to drive 4 monitors off of this machine. It has 1 AGP slot and 3 PCI-X slots. We've bought something like 5 cards already, 4 of which were "guaranteed" (by Apple in 2 cases) to be the right one. All of them turned out to be PCI Express cards, even the ones that said PCI-X on the box.

Does there exist a video card that (a) will work in a PCI-X slot, and (b) can drive two monitors?

posted by dmd to computers & internet (5 comments total)

PCI-X is (mostly) backwards-compatible with plain PCI. There are a ton of PCI video cards with two monitors, but they're made for PCs and getting them to work on the Mac will be a daunting task. Video cards on Macs are a weird murky area. ATI has made a few "Mac Edition" cards. The last PCI one was the Radeon 9200 Mac Edition. The reviews on the Apple Store say that it works in the PCI-X slots. There's a driver for 10.4.x if that's what you're running; who knows about Leopard.

However, you may best off just getting a Matrox TripleHead2Go for driving three of the monitors from one of the video outputs already on your G5.
posted by zsazsa at 2:28 PM on April 29, 2008

the Radeon 9200 is probably the only thing you can do, really, save for flashing a PC card (which is of dubious legality). Apple sells it too; that link goes to Other World Computing. the built-in drivers should work fine for that card (as Apple has sold machines with chips of that family in their own machines). if you talk to a sales rep, it helps to be very specific about which specific Power Mac G5 you have - there were a few models of them, all called Power Mac G5, with different innards (some have regular PCI, some have PCI-X, etc.), so knowing things like CPU speed and configuration can help whoever you're talking to figure out what it is you need in general.
posted by mrg at 3:13 PM on April 29, 2008

Intel really, really should have called PCI Express something else, like "SystemBus" or something. It's not related to PCI at all; it's a totally different slot.

PCI-X, on the other hand, is an extension of the original PCI standard. It (optionally) doubles both the clock rate and the bus width, giving up to a 4x performance increase over standard PCI. However, it's fully backward compatible, meaning that you can find any PCI card, plug it in, and it should work just fine.

When looking for a new video card, just drop the 'PCI-X' name entirely. There are very few PCI-X cards, and no PCI-X specific video cards at all. If you say PCI-X, people will assume you mean PCIe. Instead, just ask for vanilla PCI.

In looking over the Apple website, it looks like they still sell the Radeon 9200 in PCI form. Each card will drive two monitors, one digital and one analog. If you need to drive four digitals, for best results you'll need three cards. If some or all of the monitors are analog, you should be able to do it with two.... or, if your Mac has more than one video port (not sure on the G5), maybe just one.
posted by Malor at 3:37 PM on April 29, 2008 [1 favorite]

(I'm assuming you have a working card in the AGP slot already; if it supports two monitors of the type you need, just adding one PCI card should work. Otherwise, you'll need either two or three 9200s.)
posted by Malor at 3:39 PM on April 29, 2008

Sigh, I should think things through before hitting post.

One last possible problem: PCI is not very fast. If you're trying to run full streaming video to all four monitors at once, the G5 may simply not be able to move that much data over the PCI bus. Slideshow-type presentations should be fine, normal windowing should be fine, but if you're trying to run video, particularly high-res video, the PCI bus may not support even one monitor, much less three. You shouldn't have any problem with the card in the AGP slot, as that's much faster, but video to PCI may give you trouble.

If you wanted to do this with a modern system, you'd need a Mac Pro and two identical (cheap) PCIe video cards. Mac Pros would have no problem driving video to as many as eight screens at once, if you bought four cards.
posted by Malor at 3:44 PM on April 29, 2008