Configuring both a GTX470 and a Quadro in a MacPro 3,1

[Jason Jones]

Well, I’ve got my dual displays running off the Q4000, theoretically with the GTX470 only doing CUDA. I still get a bit of stuttering in PP, and I’m starting to wonder if it’s that I have my BlackMagic card in a PCI extender box, running at only 4X, where BM suggests a position in Slot 1 for best performance … Only so many Slot 1’s, you know?

Anyway, the Displayport-DVI adapter cable that came with the Q4000 worked fine for the second display, and Clayton’s power-stealing scheme worked great for adding a second power-hungry card to the MP 3,1.

Cheers!

[Jim Crafton]

Clayton,

First, I want to thank you for such a detailed response to this – I’m looking to do something similar and this is one of the most informative posts I’ve come across.

My situation is a little simpler, I’m trying to add a GTX 560 card to a 2008 Mac Pro 3.1 machine. I want to keep the original nvidia 8800gt so that OSX will work, and then configure windows to use the new card so that my apps there will get the boost. I don’t have any other PCI devices in the machine and only need to drive one monitor.

Given that, I have only one video power cable slot open, the other is being used by the nvidia. The 560 came with a dual 6 pin molex Y splitter cable. Do I ignore the existing video card power cable slot, and just try and follow your instructions? In other words, I’m going to try and use the power cable from the drive bay, and from there bring the cables down and into the new 560?

Or is there some alternate approach?

[Clayton Burkhart]

Hi Jim,
If there is a free slot then I would dedicate the 8800’s card instead to the drive bay feed and use both original slots for the GT card. You do need to be aware of the order and placement of the cards though. Generally, I believe the first two slots of the machine (on the bottom) should always be reserved for your video cards and I would put the GT on the very bottom (slot 1) because it should have the most lanes.

[Jim Crafton]

Clayton,

Thanks, that makes sense. I note that I only have the one cable in the Mac for the card power – do you happen to know what kind of cable I need to get? I looked around last night and I couldn’t figure out what it was. Obviously at one end it’s a 6pin molex, but the part that plugs into the mother board, I’m not so sure about.

I have an appointment at the local Apple Store today in hopes someone there will know, but I’m not horribly optimistic those guys will be of much help.

[Jim Crafton]

One other question that just occurred to me:
Assuming this all works – what do you plug the monitor into? 🙂
Sounds silly, but my understanding is that since the GTX 560 isn’t an Apple “blessed” card, the EFI bootloader will not pick it up, so if a monitor is plugged into it, you won’t see anything?
I dual boot between Windows and OSX and use rEFIt to manage this. So would this mean that I have to plug the monitor into the 8800 first on bootup, pick windows and boot into that, then plug the monitor into the GTX 560?

Thanks again!

[Clayton Burkhart]

Hi Jim,
Normally, the 2 cables that pass to the motherboard are furnished with the card. If you can’t find them, go to a local shop that has video cards and composes PC machines for the general public and ask them if they have any spare cables lying around. They usually do, or will sell them really cheap.

With the Davinci it’s important to know that your monitor cable will come from the 8800 and the GT is just used as a processor (GPU) for the application, so no monitoring from it!