4 GPUs and mac OSX

Reading on different forums appears that is now possible to run 4 GPU's for processing and a fifth for GUI in a mac configuration.

can someone confirm if this is possible, there are claims that 2 x GTX 690's do indeed seem to work with a fifth GT 120 for gui. on a 12 core 2010 mac pro

I know the Mac configuration guide for Resolve states that you can only run a single GTx 690 due to the limitation of a total of 4 cards including gui, but curious if anything has changed lately with OSX 10.8.3

or the new 2012 mac pro's

thanks

There is no way you can run a 5th. There are only 4 PCI slots on the MacPro including the standard GPU.

So at most you can use 4 GPUS

I'm not a resolve user but for a different purpose on an older MacPro have run 2 GPUs

daniel : GTX690 is 2 GPUs on one card .. so 2x GTX690 is 4 GPUs .. They are double sided .. so in MAC PRO is one free slot then, for single speed GPU .. GT120 for example ..

Cool, fair enough!

You need a cubix expander, as you'd go waaaay over on power, but yes, you can now use 2x690s and a GUI card in a MacPro.

Hi Juan

I've been following the threads about this, I noticed you did some testing, can you confirm 2 x 690's on a 2010 mac pro inside an expander?
or a 2012 mac pro

is this an update in OSX 10.8.3 that makes this possible?

2010 MacPro, just needed an SMC reset.

Yes, it seems to be a change in how the OS is addressing GPUs.

You need a cubix expander, as you'd go waaaay over on power,

or use aditional power supply and leave MAC PRO case openned .. its cheaper solution

You need a cubix expander, as you'd go waaaay over on power,

or use aditional power supply and leave MAC PRO case openned .. its cheaper solution :lol:

No, you'll NEED an external expansion chassis if you want to run 2 x GTX 690's and a GUI card.

anyone successfully running 2 x gtx 690's in an expansion chassis plus a fifth card for gui?

does system profiler list the cards no problem? does the operating system behave as per normal? does Resolve see the 2 double cards?

thanks guys


btw, my original question was regarding if and how OSX 10.8.3 now behaves in accepting more cards, I never intended to put 2 x 690's inside a mac pro, the question was about the recent new findings that allows a forth card for processing and a fifth for gui

You need a cubix expander, as you'd go waaaay over on power,

or use aditional power supply and leave MAC PRO case openned .. its cheaper solution

No, you'll NEED an external expansion chassis if you want to run 2 x GTX 690's and a GUI card.

Why ?

Without external expansion a MacPro can literally only take a single GTX 690 + a GUI Card (i.e. a Quadro 4000), and even then you still NEED additional power for the GTX 690.

If you want to run two GTX 690's plus a GUI Card in a single MacPro, the only possible way to do this is with an external expansion unit (i.e. Cubix).

anyone successfully running 2 x gtx 690's in an expansion chassis plus a fifth card for gui?

Yes - assuming you're running 10.8.3 this works fine. The OS will detect the two GTX 690's and the GUI card (for example a Quadro 4000) and everything will work as normal. Resolve with use the two GTX 690's for CUDA processing.

On the latest MacPro, this works out of the box.

As Juan Salvo said, if you're running an older MacPro, you need to do a SMC reset first.

Chris : but why? Not enough buss power ? Or why?

[Peter Chamberlain]

The Mac Pro has only two power connectors to supply extra power to internal cards. The PCI slots provide 75w each so if your GPU needs more, you need to connect the GPU to more power.... One 680 will use the two available motherboard connectors.

Thus, if you want more cards you need to find more power and one proven reliable method is using an expander.
Peter

Or use external supply for gpu.. Its cheaper than expander..

Chris : but why? Not enough buss power ? Or why?

The MacPro only has two PCI Express 2.0 x16 slot and two PCI Express 2.0 x4 slots (but with mechanical support for 16-lane cards). The bottom slot is the only double width slot.

Given the GTX 690 is a double width card, there is physically no way you can put two GTX 690's, a GUI card and a Capture Card in the same box.

Technically, you could put a GTX 690 in slot 1, another GTX 690 in slot 2 (which will also cover slot 3), then put a GUI card in slot 4 - but putting your GUI card in a x4 slot will give you horrible performance, and without a Capture Card, there's no way to accurately monitor in Resolve. In this configuration you would also need a substantial amount of external power for the two GTX 690's.

Again, for a standalone MacPro without expansion - the best configuration you can currently get is a GTX 690 in Slot 1, a single width GUI card in slot 2 (i.e. Quadro 4000) and a Capture card in slot 3. Although many people are running the GTX 690 off the internal MacPro power - it's not supported or recommended - you're much safer to use an external power supply. If you GUI card requires additional power (i.e. Quadro 4000), then you DEFINITELY NEED an external power supply.

If you need more CUDA power than a single GTX 690 - then your only option is external expansion (i.e. Cubix).

Currently it seems putting four GTX 680's in a Cubix is the best configuration you can get with Mac OS (although on Windows & Linux the GTX Titan seems to be the best option). However if you want to also put RED Rocket cards into the Cubix - then two GTX 690's seems to be a good compromise (as the 690 gives you similar performance to two 680s).

PCIeX4 is not enough for GUI card ? for example GT120 ? I understand everything u wrote next .. But it just interesting me .. We are using 4x580 in cubix in studio ..

PCIeX4 is not enough for GUI card ? for example GT120 ?

Well, it's not really supported or recommended by either Apple or Blackmagic. That said, there's no technical reason why it wouldn't work - but from the tests we've done, we found it did hinder performance.

I guess it really depends on whether you're using the system ONLY for Resolve, or whether you're using other applications or not.

The only time I'd ever really recommend putting a GPU card in one of the two x4 slots is if you want to use a RED Rocket in a single MacPro without expansion. In this case I'd put the double width GPU card in Slot 1, the RED Rocket in Slot 2, the DeckLink card in Slot 3 and a single width GPU card in Slot 4.

I have seen situations, where users have put four Quadro 4000's in a single MacPro to run large format displays - so it can definitely work.

But really, for Resolve users, I think if you're using a standalone MacPro - the GTX 690 + Quadro 4000 is your best bet. If you need more power than this, then a Cubix and 4 x GTX 680's is the next logical step.

If you HAD to put your GUI card in slot 3 or 4 - then I'd suggest using something like a Quadro 4000, rather than a GT120, because Apple and Blackmagic have optimised this card to work in these lower speed slots.

Does that make sense?

chris ; thanx for explanation ..