Dual GPUs in old (Classic!) Mac Pros

Hi There,

Hoping to create a resource for folks still running FCPX on older 2006-2012 Mac Pros in the "classic" form factor.

This topic is inspired by Alex4D's BruceX benchmark, in which fcp.co member tpayton found that FCPX 10.1 will indeed utilize at least two GPUs in an older Mac Pro.

(Topic Link: www.fcp.co/forum/4-final-cut-pro-x-fcpx/...x-benchmark?start=80 )

Here's hoping fcp.co users will use this topic to share any experiences with dual (or more, CUBIX anyone?) Graphics Cards in FCPX 10.1 and beyond for those of us looking to get some more life out of "Old Ironsides".

First Questions:

1) Is anyone aware of a Benchmark that will test specifically which functions are tied to a second, Auxiliary GPU?

2) If mixing two difference GPUs of different types, does it make sense to connect displays to the more powerful card or the less powerful card?


Thanks much for any information shared here and for taking the time to read this!

Good idea for a thread. By the way, it should be noted that of course the first thing you have to do on an older Mac Pro (2006-07) you need get Mavericks 10.9 running. In December a fellow wrote a brand new 64 bit boot loader thingamabobber (I don't want to get too technical) and a cool script to create a modified Mavericks Installer. Here is the place to get it:

oemden.com/?page_id=585

It is a bit on the geeky side, so please hit me up with any questions you have.

- T.

+1 from me. A helpful resource is Does Final Cut Pro X 10.1 render faster on Mac Pro towers with Dual AMD GPUs? What about Motion 5.1? on barefeats.com.

I am still debating whether I should get a 2nd 5770 or just save that money towards the new MP....

I honestly don't expect dramatic improvement with the 2nd 5770 but so far the magnitude of improvement I have seen from the internet (This site and Barefeats) seem to vary quite a bit and find it a little hard to make a judgement.

I have an early 2008 MP with a single 5770 and I too am intrigued by adding a second 5770. What have you seen on this site for dual 5770s that is different from Barefeats?

The forum in this site says almost 40% improvement on Bryce X benchmark

Barefeats used built-in filters and shows roughly 26-32% improvement...

Actually, I am more concerned about previewing videos in editing than cutting down export time.

I doubt the dual 5770 GPU set up will help on real time video playback during the editing process. I think a much more powerful GPU is the way to go....but if I am going this route I may just go for the new Mac Pro...

Another concern I have..or maybe not..., FCPX/Motion is the only app that supports 'dual'..what will having 'dual' do to my other apps? Some setups can cause major headaches! Trial and error I suppose.
example:
forums.macrumors.com/showthread.php?t=1583723

curious: Having dual GPU's was a big stability NO NO before on the tower. Did Mavericks solve that?

from another thread I created - before I saw this one.

My main concern......

Hello all.

I would like to install 2x 7950 cards to do a BruceX test..... but I am a bit concerned about the power? I am waiting for 2x power cable splitters.
www.amazon.com/dp/B004NNTVT6/ref=pe_3850...309540_26725410_item

concerned this will draw power from the motherboard and maybe fry it???but I should probably get a dedicated power supply?? any suggestions appreciated.

From what I have read, slot 1 and 2 are more powerful at 12lanes and 3+4 are at 4 lanes?
...then I found this:
support.apple.com/kb/HT2838?viewlocale=en_US&locale=en_US

which made me more concerned about this test...

I notice in my istat menu results (GFX-cards.jpg)


indicate that all the slots are 12v-lanes? and 1 and 2 are boosted?
(screenshot while rendering realflow and c4d)

Spec are in the screenshots.

cheers in advance.

For 2006 & 2007 models (Mac Pro 1,1 & 2,1): The best approach will be to use tpayton's method to install one 5770 in slot 1 (the bottommost slot that accommodates a double width PCIe card), and the second 5770 in Slot 4. This will use the two fastest PCIe lane combinations (x16 in slot1 and x8 in slot 4), and allow for increased ventilation, as well as leaving slots 2 and 3 open for other add-on cards. The only drawback here is the loss of Drive Bays #3 and #4 to make room for the double width 5770 on the top in PCIe slot 4.





For 2008-2012 (Mac Pro 3,1 // 4,1 // 5,1): Unfortunately only Slots 1 and 2 can run at full speed and and use x16 lanes of the PCIe bus. The top two slots (#3 & #4) will only run at x4 lanes. In the 2008 model the top two x4 slots are further reduced to PCIe revision 1 speeds. Therefore to optimize performance from GPUs in Mac Pros 3,1 // 4,1 // 5,1 both GPUs need to be in the bottom two slots (PCIe slots #1 and #2). This unfortunately reduces ventilation and blocks PCie slot #3. Many people however have run two GPUs stacked close together in this configuration without overheating problems so it doesn't seem to be a major issue.

If I'm understanding you correctly, it sounds like, in a 2008 MP, I could run two 5770s in slots 1 & 2, get full use of all of the drive bays, and just be on the watch for any overheating of the GPUs. Is that right?

Which GPU (which slot) would you use for the monitors and which for GPU work if the monitor load was moderate but continuous while the GPU work was intermittent but with intense peaks?

Installation sounds pretty straightforward, but if anyone put together a guide/tutorial, I'd be really appreciative.

Exactly correct.

Since the 5770 only requires one 6 pin power connector, you can indeed power two of them simultaneously with no risk of overdrawing the power supply.

It's pretty straight forward, here is a link to a video tutorial someone made for putting a single 5770 into their 2008 mac pro:



Adding a second card works the same way, make sure to insert it into slot #2, directly above the bottommost double width slot #1. The bottom two slots should have a small label next to them on the motherboard that reads "x16" Just make sure you connect the power cable and you should be all set.

As for which card to plug in your displays, I'm not sure it matters, as long as you make sure all displays are on the same card. I personally would go with the lower GPU in slot #1 for the displays but that's based purely on "gut" feeling.


Good luck!

This was on the BruceX topic also but I thought I would include it here:

---

Installing 2 Radeon 5770s in MacPro 2006 (1,1)

The second 5770 will go in slot 4, it will run at 8x speed opposed to 16x on slot 1, but that is the best you can do on the 2006 MacPro.. You'll need to remove any drives from position 3 and 4. After you seat the card, slip the thumb screw card holder thingie (I don't want to get too technical) under the slot 4 5770 bracket. The card will still be seated fine, just raised up a little.

Here is the cards without the thumb screw card holder thingie:





And after the thingie is screwed down:





By the way I just put in a USB 3 card from Amazon in slot 3 for just about $34 with cables. It works amazingly well. No drivers needed.

www.amazon.com/gp/product/B008V3THAC/ref...&smid=A39OX00G2TFX52

I'll post some benchmarks from the USB3 performance soon.

Hmmm, more hacking. I have a Mac Pro Early 2008 with one ATI Radeon HD 5870, would it be overkill to add another or would that get me more mileage? They are a bit more expensive than a 5770, just wondering if it would make sense?

Just installed 2x 7950's using Y splitters (yikes) powering 2x 27"LED cinema displays on the bottom card.

Model Name: Mac Pro (Early 2008)
Model Identifier: MacPro3,1
Processor Name: Quad-Core Intel Xeon
Processor Speed: 2.8 GHz
Number of Processors: 2
Total Number of Cores: 8
L2 Cache (per Processor): 12 MB
Memory: 32 GB

BruceX test - ProRes422 - average over 3 runs
1x 7950 - 50 secs
2x 7950 - 32 secs

Wow. FCPX 10.1 is a GPU monster. Give it 2 of two matching GPUs and you are going to be a happy camper. Even on a 8 year old computer. (2006 MacPro)

So the power is drawing from the port from the empty optical bay?

Some questions here, new to FCPX but decades of audio production experience...

MacPro 5,1 here, 3.3GHZ 6 core with stock 5770. Is it worth my while to install a second 5770? What actually is speeded up with the second card, rendering or smooth editing or both?

This machine currently has a BlackMagic Intensity Pro card, which I use to run a big screen for sound to picture work with Nuendo. It's good for this, but don't really need it for FCPX and anyway if I had another 5770 could I run a monitor off that (I already run 2xDVI screens from the 5770, using the DVI port and one mini display port)?

Or I could I suppose fit 2x 7950 - any comments on what to expect?

Anyone tried this combo? Any restrictions on which slots to use?

Sorry for the mass of questions, any advice appreciated....

Not using optical bay power in this case. Power is from 2 connectors on MB using 2 splitters. It did some heavy lifting last night, no worries so far.

Bare Feats did some rendering time test with a few setups.

barefeats.com/tube05.html

Not Brucex test but a comparison, nonetheless.

Thanks for the update @Brooklyntreez, good to hear your cMP is powerflifting safe and sound with dual 7950s.

Curious if anyone reading this topic might have dual Nvidia GPUs, possibly for a Da Vinci Resolve setup.

Figure the AMD GPUs will run FCPX much better since it's optimized for the new Mac Pro, but am interested nonetheless.

Anyone running dual GTX 780s with external power? Heh.

Thanks again for all the input; it's super helpful to have this information made public.

PS: Anyone out there have three or more GPUs in a CUBIX or similar PCIe expander? Thus far it seems like FCPX 10.1 has only been tested with one or two GPUs.