Dual GTX 680 4GB make my 2010 12-core Fly!

[Dr. Stealth]

Hello Stealth,

First of all many thanks for this interesting thread/post and the impressive work on the rendering job on the posted grabcad link.
At the moment I am planing to get a workstation for solidworks 2012. Since its a home project and not work related I will go for a MacPro from 2010. Now here is the question:
Since I have only one Cinema Display 27 at the moment, would a dual GPU setup make sense for me? I assume you use two displays with your setup.
I am wondering, can a MacPro with only one screen even take advantage of two cards that are not linked through SLI or Crossfire?

The hardware I have is specific to what I do. The hardware you should have should be specific to what you do. =)

I use one 27" Cinema Display. I'm a little older and, to me, multiple monitors would be too much like watching a never ending tennis match. Ny neck couldn't handle it. I have found the single 27" display to be perfect, FOR ME. I even thought a single 30" was too large when looking. I love my 27" though. Vast improvement over my first Mac that had a 9" display.

The main reason I run the dual GPUs is for the CUDA cores. This is a terrific benefit to the rendering program I use, Bunkspeed Shot. It actually cuts render time in half compared to a single GPU setup. I use Solidworks every day and it runs very well on even a single GPU.

You can think of it like this. SLI or Crossfire are for the benefit of faster smoother "Display Graphics" with the signals being sent out your video ports. Mainly for gaming. I do no gaming.

In my case my render program utilizes the CUDA cores just as if they were an extra 3,000 CPUs in my machine. They are utilized for number crunching only with the signals being sent in a loop from the rendering program, to the GPU, then BACK TO the rendering program. Not out the display port. I generally render in the background as most people do and never even watch the rendering process. It's a lot like watching grass grow. =)

Activating SLI in my case, has been seen to cause issues and actually slow down the rendering process. Nvidia (and many others) say be sure to disable SLI when using the cards as I do.

In closing I think this is what causes a lot of people confusion. I have a $600.00 Video Card in my Mac with NO display plugged into it. Seems very silly to most people, but believe me, I run the hell out of it.

Hope that helps....

 

[SilvioM]

The hardware I have is specific to what I do. The hardware you should have should be specific to what you do. =)

I use one 27" Cinema Display. I'm a little older and, to me, multiple monitors would be too much like watching a never ending tennis match. Ny neck couldn't handle it. I have found the single 27" display to be perfect, FOR ME. I even thought a single 30" was too large when looking. I love my 27" though. Vast improvement over my first Mac that had a 9" display.

The main reason I run the dual GPUs is for the CUDA cores. This is a terrific benefit to the rendering program I use, Bunkspeed Shot. It actually cuts render time in half compared to a single GPU setup. I use Solidworks every day and it runs very well on even a single GPU.

You can think of it like this. SLI or Crossfire are for the benefit of faster smoother "Display Graphics" with the signals being sent out your video ports. Mainly for gaming. I do no gaming.

In my case my render program utilizes the CUDA cores just as if they were an extra 3,000 CPUs in my machine. They are utilized for number crunching only with the signals being sent in a loop from the rendering program, to the GPU, then BACK TO the rendering program. Not out the display port. I generally render in the background as most people do and never even watch the rendering process. It's a lot like watching grass grow. =)

Activating SLI in my case, has been seen to cause issues and actually slow down the rendering process. Nvidia (and many others) say be sure to disable SLI when using the cards as I do.

In closing I think this is what causes a lot of people confusion. I have a $600.00 Video Card in my Mac with NO display plugged into it. Seems very silly to most people, but believe me, I run the hell out of it.

Hope that helps....

Hello stealth,
I am think of doing something like your dual gpus but I'm doing it for hardcore gaming. What I want to know is what geekbench score you get on that machine, like you I have upgraded my machine to dual X5690 (3.46 Ghz). and can you please post some pictures of About this Mac and system profiler?

Thanks

 

[Dr. Stealth]

Here ya go...

Hello stealth,
I am think of doing something like your dual gpus but I'm doing it for hardcore gaming. What I want to know is what geekbench score you get on that machine, like you I have upgraded my machine to dual X5690 (3.46 Ghz). and can you please post some pictures of About this Mac and system profiler?

Thanks

Here ya go... Sorry it took a while. If there's anything else specific just let me know.

So... Curious.... What's your Geekbench ?

 

[SilvioM]

Here ya go... Sorry it took a while. If there's anything else specific just let me know.

So... Curious.... What's your Geekbench ?

I get about 25K in 32 bit mode, I wonder how much will I get if I upgrade to a newer GPU. What do you think I would get If I added a GTX 690 or even two? The newest update (10.8.3) remove the 2 GB VRam limit so no more OpenCL hack, did you hack your OpenCL to take full advantage of the 8 gigs?

Thanks

 

[Dr. Stealth]

I get about 25K in 32 bit mode, I wonder how much will I get if I upgrade to a newer GPU. What do you think I would get If I added a GTX 690 or even two? The newest update (10.8.3) remove the 2 GB VRam limit so no more OpenCL hack, did you hack your OpenCL to take full advantage of the 8 gigs?

Thanks

Yes, I did the hack. But, now with 10.8.3 it's not needed.

Not sure how it works with gaming but in rendering you don't get 8GB by having two 4GB cards. The memory is separated per GPU. So if I render a 3.5 GB scene it will copy the scene into each cards ram and work fine. If I try to render a 5GB scene it wont work because the whole scene has to fit into each cards ram.

Graphics cards make no difference in Geekbench. Geekbench is purely a CPU and memory bench test. Nothing else is included in the test, it's pretty much a raw power test.

Here.... I just ran the 32bit test in Geekbench. Looks about right if your getting around 25K.

When I did my cpu upgrade the huge difference in price between the X5690 and the X5680 didn't justify the marginal speed gain.

 

[Tesselator]

Actually my MP is the server version whatever that means. Besides the OS, the only difference I could see was there was no keyboard or mouse in the box.

It means they supply you with the software needed to totally frak your system in just a few clicks.


23886... you dog you...

 

[SilvioM]

Yes, I did the hack. But, now with 10.8.3 it's not needed.

Not sure how it works with gaming but in rendering you don't get 8GB by having two 4GB cards. The memory is separated per GPU. So if I render a 3.5 GB scene it will copy the scene into each cards ram and work fine. If I try to render a 5GB scene it wont work because the whole scene has to fit into each cards ram.

Graphics cards make no difference in Geekbench. Geekbench is purely a CPU and memory bench test. Nothing else is included in the test, it's pretty much a raw power test.

Here.... I just ran the 32bit test in Geekbench. Looks about right if your getting around 25K.

When I did my cpu upgrade the huge difference in price between the X5690 and the X5680 didn't justify the marginal speed gain.

From what you said I think I might upgrade the memory too. I currently use 32GB and I am thinking of going all the way and getting 128GB, the problem is that Mac OS X only supports 96GB. Do you think I should go for the 96 or 128? Another thing I am thinking of doing Is getting two OWC Accelsior 960GB, it's a shame that the Mac Pro only supports SATA II or else I would of gotten the soon be released OWC Viper.

Thanks

 

[Kristoph]

Hi

Hi stealth,

I've just purchased the same cards and power supply. When you say you clipped the aluminium to feed the wires to the lower optical bay - do you mind me asking which tool you used?

Thanks

 

[Dr. Stealth]

Hi stealth,

I've just purchased the same cards and power supply. When you say you clipped the aluminium to feed the wires to the lower optical bay - do you mind me asking which tool you used?

Thanks

No problem... I know it's a tight fit. I actually used the tip of a needle nose plyer. The aluminum is very thin right there and a twist of the plyer will snap the aluminum.

 

[KBS756]

I specifically didn't show how I tapped into the psu as I didn't want others who maybe shouldn't be tinkering in there in the first place using this as a 'guide' which it is not. If this is 'Inspiration' to others then so be it. I myself am very comfortable with what I did and where I tapped both the 120v & 12v. The 120 came right off the main leads of the macs power cord, just inside the psu. The 12v will be very obvious to anyone who has any business in there. So the aux psu is not "drawing" anything from the main psu except the the 12v to trigger it on or off. Same as if it was plugged into a sata power connector as intended. =)

There is no relay work involved. The 12v from the psu triggers the aux psu to turn on or off. The circuitry is already in the aux psu for that.

The mod was really very simple and to me beats the heck out of snaking another 120v line through your mac and out the back and across the floor....

Plus I needed to get at the 12v anyway as I didn't want to lose my precious sata connections.

P.S. There's no prying or cutting to open the psu. half dozen phillips screws and it opens up like a clam.

Okay... Here's the 120v tap. Right off the main plug connection.

Image

Considering doing this to get a Geforce Titan or 780 in my Mac Pro without an external PSU.

what you basically did there was solder one end of the 120v to the same point as those 2 black wires? and then run it out to the aux PSU?

Thanks

 

[Dr. Stealth]

Considering doing this to get a Geforce Titan or 780 in my Mac Pro without an external PSU.

what you basically did there was solder one end of the 120v to the same point as those 2 black wires? and then run it out to the aux PSU?

Thanks

Those two black wires you see soldered to the board are what I added, they run the 120v to the aux PSU.

 

[KBS756]

Those two black wires you see soldered to the board are what I added, they run the 120v to the aux PSU.

Ok thanks, considering buying that PSU, adding it to my system then deciding on what graphics card to invest in.

Thanks a lot for the guide its very helpful

Do you have any experience with a Titan or 780?

Looking to add a singular video card to my Mac Pro to run currently 2 displays but possibly 3 in the future if I ever buy a cintiq

I do video editing and effects Final Cut Pro X, After Effects, as well as 3D Modeling, Animation, and Rendering Maya and Lightwave.

Any suggestions ?

Thanks

 

[sunsetsothickly]

The main reason I run the dual GPUs is for the CUDA cores. This is a terrific benefit to the rendering program I use, Bunkspeed Shot. It actually cuts render time in half compared to a single GPU setup. I use Solidworks every day and it runs very well on even a single GPU.

I love your setup, Stealth.

I had been thinking of picking up an old G5 Case in which to keep an extra PSU and four drives. The extra PSU being used to power a second 680 in the current Mac Pro and the four drives connected by a mini-SAS/SATA fan to a HBA in Slot 1.

One issue I can think of is getting the 2 sets of power back into the pro - probably have to remove a section from the backplate on the SAS HBA.

If the second 680 is running headless, would I be in trouble if the Mac Pro were started up without the second PSU running? I am assuming that draw would be very low unless the card was running a CUDA task or plugged into a display, but I'd love your opinion on that from the point of view of safety (ie. not burning-out traces...).

Ta

 

[Kristoph]

No problem... I know it's a tight fit. I actually used the tip of a needle nose plyer. The aluminum is very thin right there and a twist of the plyer will snap the aluminum.

Thanks for the reply Stealth.

I've just opened up my MP to remove the optical bay. The connectors are different to the aux PSU. See attached image.

Oh dear. Maybe I shouldn't embarked on this! Im a complete novice when it comes to all this. My aim wasn't to replicate your setup but to just live with having two power cords.

My machine is a 3.33Mhz Hexcore 2010 bought in the UK.

Thing is I'm kind of committed to making this work having bought the gear... Does you know if it's possible to change the connection type of the power supply? Or maybe I need to change the Mac PSU?

Im thinking this may have something to do with me living in the UK and the different connection types. Or maybe it's a newer/older connection type?

Cheers

Edit: Found I need to buy an SATA to Molex adapter

 

[Kristoph]

No problem... I know it's a tight fit. I actually used the tip of a needle nose plyer. The aluminum is very thin right there and a twist of the plyer will snap the aluminum.

Hi Stealth,

Im trying to snake the GPU cables into the lower optical drive like you've shown in one of your pics. I can see – like you say – the metal is very soft and pliable and have bent some of it clearing enough space for the connectors to go through. However my main prob is that the DVD shutter door mechanism is blocking up most of the hole. pic attached...

So Im guessing you removed the door mech to get them through? Ive removed the only visible screw and can't see any screw on the other side. This thing aint budging!

BTW just done an octane render test with both cards installed....

My iMac with a 680 renders my test scene in 2:57
The dual 680 (one 2gb and one 4gb) renders it in 1:07

That's almost 1/3 the time – Very pleasing indeed!

Cheers for the help.

edit – got them through – that was hard work,

 

[rabidz7]

Could you do me a favour? In the interest of research could you plug one 6 pin connector from the Mac into each card and one 6 pin from external PSU into the cards? So each card is powered half by the Mac and half by the external supply. The reason I'm asking is to see if the slight delay in power either from the Mac side or external PSU side causes the Mac to crash or GPU to not start. Nobody has actually done this and posted the results so you'd be the first.

The theory goes that either the power management on the GPU is clever enough to compensate for a delay in power from either 6 pin, or it is totally dependant on both 6 pin connections being live concurrently. Catch my drift?

My only advice would be to definitely have the lady in the french maid outfit dusting around the office whilst you do this.

EDIT: What's your PCI fan speed running at now? What was it before? (If you still have a EFI card to hand)

I do it in my G5 with a 7970 and it works fine, but of of course, no video out, so the 7970 is for looks. When the 7970 goes in the AMD linux box it works fine.

 

[KBS756]

Those two black wires you see soldered to the board are what I added, they run the 120v to the aux PSU.

Last Question if at first I didn't want to go into the PSU is there sufficient room to run the Power Cable through the case or in the front from the CD slot?

Thanks

 

[Kristoph]

Last Question if at first I didn't want to go into the PSU is there sufficient room to run the Power Cable through the case or in the front from the CD slot?

Thanks

See attached internal AC power lead.

One end slots into one of the PCIe slots the other end into the Aux PSU. Then another AC power lead is supplied to run from that to the plug socket.

Im not that techy but you can see that the internal lead has a cylindrical thingy – this will not fit through the hole up into the optical drive bay. Therefore making the end of the lead too short to reach the power socket on the aux PSU.

You do have to mount the drive upside down and back ass front wards like Stealth says. Also you need to switch the fans around because the stock fans are blowing in the opposite direction. No biggy even for me.

So anyway Ive ended up running the other external AC power lead straight out through the DVD slot. Yep it looks ugly as hell. But it works.

If you come up with a better solution then let me know. Im not messing around drawing power from the stock PSU though – not without a detailed how-to guide!

 

[KBS756]

See attached internal AC power lead.

One end slots into one of the PCIe slots the other end into the Aux PSU. Then another AC power lead is supplied to run from that to the plug socket.

Im not that techy but you can see that the internal lead has a cylindrical thingy – this will not fit through the hole up into the optical drive bay. Therefore making the end of the lead too short to reach the power socket on the aux PSU.

You do have to mount the drive upside down and back ass front wards like Stealth says. Also you need to switch the fans around because the stock fans are blowing in the opposite direction. No biggy even for me.

So anyway Ive ended up running the other external AC power lead straight out through the DVD slot. Yep it looks ugly as hell. But it works.

If you come up with a better solution then let me know. Im not messing around drawing power from the stock PSU though – not without a detailed how-to guide!

Thanks what I needed to know ! I will probably do it the way Dr.Stealth laid it out but will do that when I have time if I can run and test it that way.

 

[Dr. Stealth]

Ok thanks, considering buying that PSU, adding it to my system then deciding on what graphics card to invest in.

Thanks a lot for the guide its very helpful

Do you have any experience with a Titan or 780?

Any suggestions ?

Thanks

No Titan or 780 experience but from what I've seen the 780 is nearly identical to the 680. It may even accept the 680 EFI roms.

No suggestions on the rest. Your apps and workflow are vastly different than mine.

 

[KBS756]

No Titan or 780 experience but from what I've seen the 780 is nearly identical to the 680. It may even accept the 680 EFI roms.

No suggestions on the rest. Your apps and workflow are vastly different than mine.

K thanks I believe the 770 is the one that is like the big brother of the 680 (Overclocked 680) I think the 780 is a different architecture a somewhat neutered version of the Titan

Thanks again for all the help your thread has been!

 

[Dr. Stealth]

I love your setup, Stealth.

I had been thinking of picking up an old G5 Case in which to keep an extra PSU and four drives. The extra PSU being used to power a second 680 in the current Mac Pro and the four drives connected by a mini-SAS/SATA fan to a HBA in Slot 1.

One issue I can think of is getting the 2 sets of power back into the pro - probably have to remove a section from the backplate on the SAS HBA.

If the second 680 is running headless, would I be in trouble if the Mac Pro were started up without the second PSU running? I am assuming that draw would be very low unless the card was running a CUDA task or plugged into a display, but I'd love your opinion on that from the point of view of safety (ie. not burning-out traces...).

Ta

If I remember correctly I think I fired my mac up without power to one of my cards and it wouldn't boot. The gpu's rom is read at boot time and if there's no power to the card an error message pops up telling you so. I don't believe you can get past it.

----------

K thanks I believe the 770 is the one that is like the big brother of the 680 (Overclocked 680) I think the 780 is a different architecture a somewhat neutered version of the Titan

Thanks again for all the help your thread has been!

Ahhhh Yes! I knew it was something like that. =)

 

[Dr. Stealth]

Last Question if at first I didn't want to go into the PSU is there sufficient room to run the Power Cable through the case or in the front from the CD slot?

Thanks

I think the CD slot would work just fine for a temp setup. Others have run the power in through a PCI cover in the back.

https://forums.macrumors.com/threads/1460429/

 

[OrangeSVTguy]

I think the CD slot would work just fine for a temp setup. Others have run the power in through a PCI cover in the back.

https://forums.macrumors.com/threads/1460429/

I ran that power behind the PSU and out the back into a mini plug. This did require putting a hole through the back of the case.

 

[Gymnut]

Got a refurb EVGA 580C on the way from EVGA(reasonably priced with a 1 year warrranty vs. buying USED on eBay with no warranty).

I went ahead and ordered the FSP booster from Newegg but was wondering whether I could run the booster externally(at this point I think I'd opt to leave the side cover off), without tapping into the main PSU?

First time dealing with a power supply, but I would assume that there would be no ON/OFF switch on the FSP booster, and that as long as it was plugged in, it would be providing power to the card.

I know the benefit to tapping into the main PSU is it would be slave to the main PSU whenever the MP is powered on and shut down. I've got a Pioneer BDR drive that unfortunately I still need in the upper bay, as well as a OCZ Vertex4 with my OS in the lower optical bay; At this point I'd rather not sacrifice a SATA connection and all four HD bays are full.

Currently all my PCIe slots are full as well:

4: Blackmagic Intensity
3: Matrox CompressHD
2: Highpoint Rocketcache 3240x8
1: EVGA 570 2.5

I'll probably swap out the 570 with the 580 because I can't move the Highpoint up to a x4 slot since it's a x8 card.

Again, just wanted clarification that it'd be all right to run the power supply outside the case without connecting to the main PSU(like Dr. Stealth has pictured in Post #1).

Thanks in advance.

Edit: Was also wondering whether the FSP Booster is safe to run with the 580 Classified Ultra. According to EVGA specs, it says a minimum 600 watt power supply.