Mac Pro 5,1 - Can i run 6 GTX Nvidia?

[philliplakis]

Hi

I have a mac pro 5,1 12 core machine.

currently running gtx 120 (Screen)
and 780 ti (Octane render)

I don't use the 780ti for anything other than its cuda cores to render images.
i have a large project coming up and i am wondering if i could run the following ?

i just need my mac to recognise they are there

pcie slot 4: GTX 120 (If the efi 980 isn't ready)
pcie slot 3: 4x to 16x riser - GTX 970 or GTX 980 macvidcards. (when its done)
pcie slot 2: 16x to dual 8x ribbon - Dual GTX 970
pcie slot 1: 16x to dual 8x ribbon - Dual GTX 780ti

basicially i don't need to be attaching cords into them. they would be just there to feed octane render.

In the mining forums which they use cuda aswell they only get 5-10% reduction in performance running similar setups on PC so just curios if this will work on a MAC and if not what is the Maximum?

PS. I know about power supply this is not the question i am asking...

[bepeg4d]

Very interesting, do you have a link for this 16x to dual 8x ribbon?
ciao beppe

[philliplakis]

Very interesting, do you have a link for this 16x to dual 8x ribbon?
ciao beppe

Here are some i found,

http://www.mypccase.com/pcduricawfls.html
http://www.ameri-rack.com/ARC2-458_m.html
http://www.compsource.com/pn/RSCR2UGA2E ... 2UGA2E16A/

Its not as simple as plug and play you can't use a ribbon,
you need to use these boards that split the signal,
and from these boards they run powered x16 risers from ePSU.
eg.
http://www.ebay.com.au/itm/360870273585 ... 1423.l2649

They say to use the same card on each channel, They only lose 5-10% performance...
They have 8 running perfect on LINUX one guy has 16 on LINUX, Win 8 Max is 6, and Win 7 they say 5 but people have 6 running...

[bepeg4d]

wow, a bit complex for my hw skill
it's necessary to study a lateral structure for fitting the cards
anyway please, get me informed on this, it could be an interesting solution, if the performance drop is so relative low
ciao beppe

[philliplakis]

it's necessary to study a lateral structure for fitting the cards

? you got me on this one, what do you mean?

[Diz1]

I haven't had much success with riser cards in Macs, after installation my Mac Pro Tower 5,1 just didn't see the cards. Has anybody else got them to work?

I am currently running a new MacPro 6,1 with 3x 780Ti on the 3 thunderbolt buses as eGPUs. I tried more but if there is more than 1 card on each bus, the mac won't even start.

I'd be very interested to get more cards working on either MacPro 5,1 or eGPU, anybody else try something?

[3dworks]

there will be a problem with the internal power supply not feeding enough current. also, be warned that there is a OS imposed limit of 2 supported CUDA cards in a mac pro nowadays. after the 10.9.1, OSX will not allow you to use any more than 2 CUDA cards. but there seems to be the exception when the 780 black titan card is used, better read for yourself here: http://forum.blackmagicdesign.com/viewt ... ix#p154741 and here: http://forums.macrumors.com/showthread. ... st18847118 or in the netkas forums http://forum.netkas.org/index.php/topic,8403.15.html ...

i have a mac pro 5,1 with an internal mac flashed 780 gtx card and a netstor expansion box for 4 cards here. under CUDA 6.5.18 and OSX 10.9.5 with nvidia web drivers, i can work with 2 extra 780 gtx cards (not ti series), with a trick. only reverting to 10.9.1 or 10.8.x will list the third card in the box, a 680 gtx 6G VRAM card. curiously, if i remove this unseen card under 10.9.5, only two 780 cards are seen by the system, the internal mac pro card and one in the expansion box. the trick is to use the 3rd card in the expansion box as an 'activator' for the other two cards. sure not an economic solution, but i reboot to 10.9.1 from an separate SSD if i really need the fourth card's render power.

unfortunately, apple seems not to have solved the issue with yosemite, but maybe the complainings from so many pro users in the video postpro area (da vinci resolve) will make some pressure on them. seems that apple focussed totally on the new macpro architecture when changing this and didn't look back.

so my advice is to inform yourself via the blackmagic forums about the configuration you are looking for, as it seems to be almost dark science to find the right setup working when in need of more than 2 cards nowadays. if you still have 10.9.1 installed somewhere, keep it to use all the CUDA cards until apple fixes this or a third party hack is found.

cheers

markus

[Diz1]

Thanks for the heads up Markus, all very useful and interesting stuff. I will quit while I'm ahead with my setups!
Apple really doesn't seem to give a flying fig about the pros any more.

[philliplakis]

I haven't had much success with riser cards in Macs, after installation my Mac Pro Tower 5,1 just didn't see the cards. Has anybody else got them to work?

I am currently running a new MacPro 6,1 with 3x 780Ti on the 3 thunderbolt buses as eGPUs. I tried more but if there is more than 1 card on each bus, the mac won't even start.

I'd be very interested to get more cards working on either MacPro 5,1 or eGPU, anybody else try something?

yes riser cards work, they must be powered though... I'm running a gtx 780 3gb off one. i have another ready to install just waiting for another riser cable.

i have a mac pro 5,1 with an internal mac flashed 780 gtx card and a netstor expansion box for 4 cards here. under CUDA 6.5.18 and OSX 10.9.5 with nvidia web drivers, i can work with 2 extra 780 gtx cards (not ti series), with a trick. only reverting to 10.9.1 or 10.8.x will list the third card in the box

cheers

markus

thanks for all the info, your a legend...

just curiously i don't have a back up of 10.9.1 or 10.8.x is there somewhere i can get one?

[Diz1]

I see, wasn't using powered risers! Thanks!