2 x GTX 480 on two separate PSUs?

[branskyj]

Hi all,

 

would it work if I install two GTX 480s on a PC and feed them with two separate PSUs. One of the PSU will be the main one (it will feed all the components on the PC with electricity including the first GTX 480) and the second will be dedicated to the second GTX 480.

The GTX 480s I have picked are already straining my budget and don't want to by a single 1000W+ PSU.

Could such configuration cause any problems?

 

Any help would be appreciated.

Thanks.

[AJLynn]

No, it wouldn't. Two problems - you'd need a case that holds two power supplies, and the power supply is triggered to turn on or off by the motherboard which is receiving a signal from the power button on the front of the computer - how would you simultaneously turn on two power supplies?

 

Next question: why the heck would you put two of those things in one PC?

[branskyj]

Crap, how did I not think of that? So obvious. As far as available space goes- I've stacked up my 4 PCs in a metal filing cabinet, a micro render farm of my own.

I need the two GTX 480s for GPU rendering under Octane. Just like with the CPUs turns out one can never have enough GPUs either.

 

Thanks a lot AJLynn. You just saved me a lot of trouble.

 

On a side note- I just found that online. Do you think a transitional cable lie the one on the picture would help with the mobtherboard/PSUs problem?

Edited August 10, 2010 by branskyj

[Jeff Mottle]

It is possible, let me find out an answer for you. The guys over at Renderstream have been doing this for a while for high end GPU render farms. I will post back with an answer shortly.

Edited August 10, 2010 by Jeff Mottle

[branskyj]

Thank you very much, Jeff

 

In the meantime I found this- http://aphnetworks.com/tutorials/psu_paperclip_trick

It's called "the paperclip trick"- could that be what you were looking for?

 

Thanks again.

[Jeff Mottle]

Hmmmm, that's called asking for your house to burn down. I personally would not risk it. Jon from Renderstream is going to post on here soon, but he did tell me on the phone that you needed a server class MB that can handle multiple PS. He said there was also a power booster from Thermaltake as well. I'm curious though, why do you want two power supplies? You could buy a single 1200W PS and it should be plenty to handle two 480's

[branskyj]

Well, the two GTX 480s will cost about 1000 GBP and to be honest that is already too much for me but still doable. On the other hand I have 4 very good PCs so I figured why not put two of the PSUs into use.

Since I cannot afford a server motherboard at the moment either I guess I will have to just squeeze somehow 150 GBP for a 1200-1500W PSU.

 

Thanks a lot again, Jeff.

[AJLynn]

I don't know what the market looks like in the UK but here, Newegg will sell you a Cooler Master, Corsair, Thermaltake or Antec 1000W PSU within your budget. The Antec True Power Quattro 1000W would do the job.

 

Also, I don't know if you can make this happen, but I think that if you run the numbers, 3x GTX 470 is 20% more CUDA power than 2x GTX 480, for 5% more money. Now I haven't seen actual benchmarks for any of this, but that's my interpretation of the cards' stats.

[branskyj]

I was actually going to get two GTX 470s but they come with maximum of 1.2GB of VRAM. The GTX 480 has 1.5GB VRAM and when it comes to GPU rendering every last MB counts (2x 1.2 GB or 2x 1.5 GB does not give you 2.4 GB or 3GB in total) especially when doing arch viz.

When it comes to rendering power 480 is about 30% more powerful than the 470 under Octane so yes- you have a point there but the VRAM issue is still there and as far as I know that is with all GPU renders at the moment.

Thanks for the PSU suggestions by the way. Will look into them now.

[Mr.Ping]

my existing psu CM 1100w can still handle if i transfer it to a system with SR-2 dual xeon & sli gtx480?

thanks!

[AJLynn]

Actually, I have no idea. The EVGA SR-2 motherboard is HPTX form factor and has more than the usual number of power connectors. It's very difficult to find a case for it (it doesn't use EATX cases) and EVGA is going to launch its own power supply to go with it.

 

This is why I used EATX parts from Supermicro in the dual Xeon on 3datstech.com.

[John.RenderStream]

We build systems with up to 8 - 16 GPU and routinely use multiple PSU to power them. I think in your case the Thermaltake Power Express 650W is what you need. The unit fits in the drive bay so make sure you have a spare to work with and comes with everything you need to integrate it into your system. Our main issue is that it requires an additional power cord that fits through a PCI slot adapter so to us it works in a pinch but lacks elegance.

Diagram of Power Express 650W wiring:

[ATTACH=CONFIG]38636[/ATTACH]

 

http://www.thermaltakeusa.com/Product.aspx?C=1264&ID=1544

 

Finally just a comment on the GTX480 we find under a full load it will pull up to 327W so you will need all the PSU you can get. Also you may need to add more cooling. Overall while it has fewer shader-cores I suggest you should consider one FX4000 card with 2GB memory and then add another later.

Good luck

John from RenderStream

(apologies to Jeff for my delayed response)

[branskyj]

Thank you very much for the help, John.RenderStream. I wasn't aware of such a thing. I am checking it out right now.

 

Cheers.

[tecton3d]

Actually, I have no idea. The EVGA SR-2 motherboard is HPTX form factor and has more than the usual number of power connectors. It's very difficult to find a case for it (it doesn't use EATX cases) and EVGA is going to launch its own power supply to go with it.

 

This is why I used EATX parts from Supermicro in the dual Xeon on 3datstech.com.

I spec'd an SR-2 system for a friend and we found that the Lian Li P80 works with the HTPX form factor and found it a much better option than the Mountain Mods offerings, for obvious reasons.

 

We also went with the Antec 1200 PSU and it seems to be working great although he is only going with a single GTX 470 instead of multiple 480's.

[tecton3d]

We build systems with up to 8 - 16 GPU and routinely use multiple PSU to power them. I think in your case the Thermaltake Power Express 650W is what you need. The unit fits in the drive bay so make sure you have a spare to work with and comes with everything you need to integrate it into your system. Our main issue is that it requires an additional power cord that fits through a PCI slot adapter so to us it works in a pinch but lacks elegance.

Diagram of Power Express 650W wiring:

[ATTACH=CONFIG]38636[/ATTACH]

 

http://www.thermaltakeusa.com/Product.aspx?C=1264&ID=1544

 

Finally just a comment on the GTX480 we find under a full load it will pull up to 327W so you will need all the PSU you can get. Also you may need to add more cooling. Overall while it has fewer shader-cores I suggest you should consider one FX4000 card with 2GB memory and then add another later.

Good luck

John from RenderStream

(apologies to Jeff for my delayed response)

Is it preferred that one uses multiple PSU's on systems with multiple graphics cards instead of a single, more powerful PSU? Does it extend the life of the main PSU or increase reliability? I know the above was reference due to the fact that the builder already has a 1000w and not enough budget for a larger PSU.

 

The reason I ask is that I'm spec'ing a workstation SR-2 system myself and will be running mutliple GTX470's (at least 2 - perhaps adding more later) and will of course, overclock each xeon.

[AJLynn]

Good to know, Daron. Guess I'll have to think about whether it makes sense to use that next month.

[tecton3d]

indeed. The case is loaded with features and for $300 it should be. Another thing to consider is that though the motherboard itself is gigantic but the other hard part is finding a case with 10 slots for the SR-2.

 

... sorry for the hijack

Edited August 14, 2010 by tecton3d

[John.RenderStream]

No you don't need multiple PSUs except under the most arduous situations such as working in enterprise-class / production environment where they can also supply redundancy as well as overage support or, as is our case, if you simply can't get enough power, which is what we see with our eight and sixteen GPU solutions.

 

May I ask why the 470 over the 460? Also, how many cards do you plan to add ultimately?

[tecton3d]

No you don't need multiple PSUs except under the most arduous situations such as working in enterprise-class / production environment where they can also supply redundancy as well as overage support or, as is our case, if you simply can't get enough power, which is what we see with our eight and sixteen GPU solutions.

 

May I ask why the 470 over the 460? Also, how many cards do you plan to add ultimately?

 

thanks for the clarification.

 

470/460 ~ I read on the forums @ refractive that the 470 was the best bang for the buck when using octane... and, the 470 comes is available with more Vram though I just now found the Palit gtx460/2gb version which looks like a nice piece of hardware for GPU rendering considering it's price and massive 2gb's of Vram.

 

I'll be starting with one card then upgrading if I think Octane has a place in my future... to 4 cards if the strain on the system isn't absurd as I'll also be overclocking dual E5620's. As of now, I have the Antec TPQ-1200 1200W spec'd for the build (6 dims, 2hd's, 6 fans). Of course the other option for Octane is to use any available cuda graphics card on any computer in the network to also render on a-la distributed rendering, thus not loading a single system with multiple gpu's. I have one other machine (old workstation that will be converted to a file server) that can house 2 cuda cards and would take the strain off of the primary workstation... Is this something you would recommend over multiples on a single workstation system?

Edited August 16, 2010 by tecton3d

[AJLynn]

2 Xeons and 4 470's on an SR2? Now that would require more than one 1200W PSU, but I'd like to see how fast it can tear through a CUDA render...

[John.RenderStream]

I think a single system with multiple cards always has the potential of being better but you will need to plan for more power 1200W won't cut it. But not working with Octane yet I feel unqualified to comment about its capability in a farm.

 

From the looks of it the Octane dependencies with the CPU is the QPI not the pure processor speed. So we hope to build a lab system soon and put it through its paces. We are looking at X5680 and E5620 single and dual, one to eight GTX480 and one FX5000 and up to seven C2050 but maybe we will add the 470 and the 460 to the mix.

 

 

 

thanks for the clarification.

470/460 ~ I read on the forums @ refractive that the 470 was the best bang for the buck when using octane... and, the 470 comes is available with more Vram though I just now found the Palit gtx460/2gb version which looks like a nice piece of hardware for GPU rendering considering it's price and massive 2gb's of Vram.

 

I'll be starting with one card then upgrading if I think Octane has a place in my future... to 4 cards if the strain on the system isn't absurd as I'll also be overclocking dual E5620's. As of now, I have the Antec TPQ-1200 1200W spec'd for the build (6 dims, 2hd's, 6 fans). Of course the other option for Octane is to use any available cuda graphics card on any computer in the network to also render on a-la distributed rendering, thus not loading a single system with multiple gpu's. I have one other machine (old workstation that will be converted to a file server) that can house 2 cuda cards and would take the strain off of the primary workstation... Is this something you would recommend over multiples on a single workstation system?

[branskyj]

As far as I know Octane does not support distributed rendering. Which means that using multiple GPUs over a network of PCs is not an option. On the other side the software is extremely powerful and 2-4 high end GPUs will satisfy most of people's needs. I personally just ordered two Palit GTX 460 2GB (slightly overclocked) and hope for a cuda 3.2 which supposedly will fix the issue with available CUDA cores on the card. TWo GTX 460s will also spare me the need to shoot myself when I get my next electricity bill and won't require a PSU upgrade

Cheers.

[AJLynn]

I thought they were supposed to fix that in the latest beta?...

[branskyj]

No, in the latest 2.3 distributed rendering is still not implemented. Not when it comes down to rendering single frames. To quote Radiance (the man behind Octane)- "...you can render animation frames with any scriptable network render queue".

[tecton3d]

No, in the latest 2.3 distributed rendering is still not implemented. Not when it comes down to rendering single frames. To quote Radiance (the man behind Octane)- "...you can render animation frames with any scriptable network render queue".

 

well that's good to know and thins down my choices for hardware then.

 

I'm very exited to hear how your Palit 460/2gb's work out.