Emperor of Mac Pros ;-) Dual GTX 970 GPGPU OS X

Ladies and Gentlemen , the emperor has entered the room - a fully functioning, dual high performance Maxwell Compute GPU Mac Pro running OS X . He sips power and breaths fire and was born earlier today . Enjoy and do not forget : The Nehalem Mac Pro remains a very robust machine .

Luxmark SALA (GPU only) seems to be a top score for a real Mac at 4499 .

Finally , a video subsystem that can handle both high performance Open CL and Cuda Core hardware acceleration . And everything powered internally from the factory .

Details are in the pictures , but a summary of the hardware profile is as follows :

Mac Pro 4,1 > 5,1 (Factory 2009 )
Hexacore 2.8 GHz
2 x EVGA GTX 970 Superclocked
Sonnet Tempo Pro Plus with 2 X 256 GB Samsung 850 Pro RAID 0 .

He's been benchmarked in Blender (Cuda) , Luxmark (Open CL) , Black Magic (Drives) and Heaven / Valley .

This cat is getting sleepy and needs to take a long nap . Additional information will be provided tomorrow and I will reply as best as possible to all requests

Hello , Prince . Thank you very much for inspiring and advising me on how to build my first GPGPU array in a Mac . I used a pair of Sapphire reference AMD 7950 cards and got quite respectable results with FCPX . I build systems locally and soon discovered also a very high performance storage system is a requirement in order to write all the data being processed quickly enough to avoid latency issues . And that means , these days, the best PCIe flash/SSD card available .

With all due respect, my video subsystem is already outperforming your pair of AMD 7970 cards in Open CL . Which is why I called the build , “The Emperor.” Your Luxmark Sala score includes the contribution of a pair of X5690 Xeons . My Sala score is just from the pair of GTX 970 cards . I didn't even think to add my CPU to the mix . I think publicly you stated your Xeons added about a thousand points to the Sala score , which would bring your 5146 score down to 4146 .

If you like , I can add a 12 Core @ 3.46 GHz Tray into this Mac and see what happens

But all the rendering action these days seems to involve compute video arrays and high speed secondary storage systems . CPUs are not an economical contributor to rendering operations . And I'm already recommending to local still image / video clients on a budget that they should use single processor 6 Core Nehalem Mac Pros and simply build up the video and drive arrays to achieve the performance they need at a price tag they won't recoil from . These rigs are not cheap as it is ...

Additional profile information :

Video cards used : 2 x EVGA GeForce GTX 970 Superclocked ACX 2.0 04G-P4-2974-KR

OS X version used : 10.10.1 Yosemite .

nVidia Web Driver version used : 343.01.02f01

nVidia Cuda Driver used : 6.5.25

I have had no problems with this combination of drivers so far . Everything seems to work and remains stable so far , but I am worried about the system breaking with an OS X or driver update .

@drewsof07

Yes, the logic is , it works under load without a mushroom cloud over the Mac !

Keep in mind , the reason cMP workstations look so pretty under the hood is because Apple routes the massive 980 W from the PSU into motherboard traces (and from there to connectors feeding system components ) . These traces are fragile compared to cables directly from the PSU as is found on the PC side . So, it's best to be conservative and not risk melting the traces when components are placed under load for an extended period . It's safer to spread the provided power over as many points as possible to a component .

Also , I don't think it's just a matter of total watts provided . I think it is more a matter of how the power is distributed across the three points each video card is powered from (the PCIe slot and the two 6 pin PCIe booster power connectors ) .

With previous GPGPU builds involving two AMD 7950 cards, I discovered I needed to provide a potential total of 225 W to each card even though under load each card only consumed around 130 Watts . That required each card to receive power from the PCIe slot and two 6 pin booster cables , even though the max power was never used . The cards would not work unless all three power points were fed . The GTX 970 cards are probably in the same boat .

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Total watts used, system wide, when the pair of GTX 970 cards are used at load in rendering does not exceed 450 W in this Mac . CPU was not used that much , intentionally . This high performance build is energy bill friendly thanks to the power sipping nVidia Maxwell GPU chips .

@drewsof07

Also, each cMP SATA HDD backplane cannot provide the 75 W of power a 6 pin PCIe power booster cable is rated for . I would not exceed 35 W from that point for safety reasons alone . Remember , these backplane connectors are intended to feed a single HDD . 4TB Mechanical drives consume maybe 9 W maximum . So, in reality , the maximum power provided to each GTX 970 in this build is likely 75 W (PCIe slot) + 75 W (motherboard mini PCIe 6 pin connector ) + 35 W (backplane) = 185 W . Each card draws only a total of 135 W at load , evenly and safely distributed . This is a very conservative build . See the enclosed Max power draw figures in this chart showing this build in action .

last post for now as I have a day job lol .

for those of you familiar with blender and Mike Pan's classic BMW benchmark rendering test , here is the result for this dual GTX 970 build using Cuda Core hardware acceleration : 22.85 seconds .

@kennyman

I need to transfer a copy of FCPX onto the drive first . It's a newly created OS installation and it took me forever just to load OS X because the Sonnet card did not like my local USB OS installation flash drives . So, it was a longgggg download from Apple's servers . To be fair to Sonnet, their card is uniformly awesomely fast with all OS X versions from 10.6.8 Snow to 10.10.1 Yosemite . Around 850-950 MB/s sequential reads and writes with the two Samsung 850 PRO SSDs in striped RAID .

@crjackson2134

No Maxwell video card has EFI roms yet , so these are just PC Editions . Also, no drivers are in Mac OS X for these cards . All drivers are straight from nVidia and must be loaded first before the cards are installed , or you'll get a black screen for sure at start up. I'm going to enter this build in EVGA's Mod Rigs program , hopefully to encourage their engineers to produce a Mac Edition . If anyone can , they will . EVGA made the GTX 285 and 680 Mac Editions .

@Pressure

Bresink Hardware Monitor reports the total power consumed by each card to be around 135 W at load .

See chart in post #13 , Max figures for the Hard Drive (Backplane) number 3 and 4 , PCIe Boost 1 and 2 (six pin mini PCIe mobo connectors) and PCIe slot 1 and 2 figures . These are the six power points the two cards jointly used . Max figures are when the cards were at load .

Also , the power consumption figures were independently verified with an externally attached Kill-A-Watt device . System power consumption was 128 W at idle (this figure includes the 20 W the two GTX 970 consume at idle) . When only the two GPUs were at load rendering , system power consumption peaked at 414 W . 414 – 128 = 286 . 286 / 2 cards = 143 W max consumed additionally by each card at load . Plus , each card idles at 10 W (which we need to add ) so let's say each card consumes an absolute maximum of 153 W at any time .

@ongnoi

Thanks

All you need to do is install a GT 120 Mac Edition for your UI needs in an available slot and install the GTX 970 again for Compute purposes . Compute GPU cards work best anyways when they have no video channels connected to displays . The GTX 970 only works in Yosemite , though .

@Pressure

What you require for extreme precision, then , is what I lack in my shop – a Mac Pro Nehalem test bench with a bench multimeter and lots of current probes and a custom PCIe riser to get enough access to measure the various rails simultaneously . What I do have is accurate enough to serve me from a pragmatic system build standpoint . Good enough to build GPGPU arrays that are stable and safe at load .

I am perfectly satisfied with my methods – the Mac's built in sensors are accurate enough and are read properly by Hardware Monitor . Coupled with a Kill-A-Watt device that reports real time system consumption wattage , I have an excellent idea of the load various components pull at any given time under controlled circumstances .

If you maintain that each GTX 970 pulls 180 W at load , then two should pull 360 W simultaneously . This entire Mac Pro system pulled a maximum of 414 W when both GPUs were at load . Which means the rest of the Mac would be consuming just 54 W . This is absurd since a cMP PSU alone wastes around 50 W worth of power just by being turned on .

I'm quite certain these cards at load do not exceed more than 153 W each of power in my system . That's credit due to the Green Team at nVidia designing a power sipping GPU .

I might take the opportunity to install these cards in my Windows test bench , where I can evaluate these GPUs more accurately . But it will not shed any light on how they perform in a Mac Pro under OS X .

FCPX BruceX score is 101 seconds . This is an average of three scores , as recommended by the author . Both GPUs were involved in the processing , but only at around 35 percent load each . The load was equally balanced simultaneously across both cards . Obviously, the cards are underutilized with the test . Drivers not mature enough ? I'm using outdated drivers because they are known good . Maybe I'll do a little experimenting . Any thoughts ?