Project GPUBox: External GPU case.

[Yukikaze]

It would be interesting to see how cable lenght affects performance!

It really shouldn't. PCIe has a very high latency as it is (compared to RAM), so the cable length will not add anything measurable. Assuming no loss of signal and no interference (and we do not suffer anything measurable here at work, even with massive amounts of electronics around our testbeds in the lab) the actual effect should be nothing a human will care about.

 

[Swamp Monster]

Wow, 50cm is really long! I would be happy if there is no interference, because it means that I can make similar cable and box myself. I like the idea of GPU outside of a case in a box. I hope it works. It would be good for OC'ing too, because you can add any extra cooling you want!

 

[Yukikaze]

Well folks, it works! Typing with one of my GTX470s running off the PCIe extender!

Gonna run some 3D benchmarks to load up the card and check how the performance is looking like. Pics will be uploaded when I am done!

Here's a GPU-Z for now:

 

[[Ion]]

This is a very cool concept, subbed!!

 

[Yukikaze]

And here are the promised pics. From what I can tell, the card is working just fine. The one thing that looks strange to me is the fact that the card reports x4 Gen1 lanes rather than x4 Gen2 lanes in GPU-Z, but I'll inquire with customer service about the possible cable lengths for PCIe Gen2 traffic.

Concept proven, time to order cables!

The PCIe extender connected to my rig:

Here it works:

Here's the card humming along on the extender:

And here's some Mass Effect 2 goodness. Card load at 98 or so percent can be viewed on the left monitor:

 

[wolf]

that extender is awesome! I wonder how 4x will affect the performance of the card overall.

 

[Yukikaze]

that extender is awesome! I wonder how 4x will affect the performance of the card overall.

There is a PCIe scaling article here on TPU. However, the end product will be running x16 extenders, so that won't be an issue. I just couldn't find a x16/x16 extender at work to drag home for testing.

EDIT: Samtec has been e-mailed about their longest PCIe x16 Gen2 extenders. As soon as they send me a catalog number I'll order the extenders!

 

[wolf]

There is a PCIe scaling article here on TPU. However, the end product will be running x16 extenders, so that won't be an issue. I just couldn't find a x16/x16 extender at work to drag home for testing.

yeah the article was on the 5870 and pci-e sacling, as i remember it was able to deliver 75% of its 16x performance at 1x, so 4x should be plenty, but GTX400/500 series cards might be different.

good to know the end product will be 16x links, I am very interested in this project and want to do it myself sometime in H2 of this year

 

[blu3flannel]

This is totally awesome! Have you decided what type of enclosure you will be working with yet?

 

[Yukikaze]

This is totally awesome! Have you decided what type of enclosure you will be working with yet?

Not yet. Still waiting to see what length of cables I will end up with. Once I know that, I'll be able to design the enclosure properly. If the cables will be short, I will have to build an enclosure myself: In this case the cards will be vertical with the exhaust ports on the top and the base slots of the extenders aligned so that they face the rear of my main case to make the best use of the short length of the extender. If I can get 500mm cables, then I might use a regular case because the length will allow me to place the case back-to-back with my case and still reach the side where the motherboard tray is.

I am leaning towards the first option in either case, though, because it will be more compact and my desk is full of stuff.

 

[Swamp Monster]

I have no idea why it reports only PCI-E gen1. Has this extender a electronic circuit on it? Maybe GPU-Z just looks at avaliable brandwidth? Just guessing. I think W1zzard should know that. An I still think - shorter is better ,regarding to cables.

 

[Yukikaze]

I have no idea why it reports only PCI-E gen1. Has this extender a electronic circuit on it? Maybe GPU-Z just looks at avaliable brandwidth? Just guessing. I think W1zzard should know that. An I still think - shorter is better ,regarding to cables.

No, the extender is completely passive. GPU-Z reports the actual link width as well as generation, so unless there's a bug in it, it reports the right thing. I can think of two reasons why this might happen, though:
1) Link establishment failed at Gen2 signaling rates due to cable length and it fell back to Gen1 and worked.
2) My motherboard decided to only establish a Gen1 link because it detected than not all 16 lanes were connected (For some weird reason or other).

You are quite right that shorter is better, too, but I need some length to play with to make this viable.

 

[Swamp Monster]

Yes, it could be reasons you mentioned. I guess we will find out when you get the right cables(x16 to x16). Waiting for that. You will need to think of longer PSU cables or maybe you will put another PSU in "GPU box"?

 

[Yukikaze]

Yes, it could be reasons you mentioned. I guess we will find out when you get the right cables(x16 to x16). Waiting for that. You will need to think of longer PSU cables or maybe you will put another PSU in "GPU box"?

I already said before that I'm planning on a second PSU in the GPUBox itself. I have a Hiper Type-R II 880W PSU on standby.

 

[Swamp Monster]

Good thing you have spare PSU to throw in there. I am waiting to see the end product. Think of how good it would look in plexiglass box!

 

[(FIH) The Don]

fucking awesome

 

[Yukikaze]

A setback has occurred. This morning my 3SLI eVGA X58 motherboard died. It will POST and immediately lock up. I have replaced it with my older DFI LP DK X58-T3eH6 and I was back and running pretty quick (with the added bonus of having cleaned my rig from any dust with an air compressor), but my older board, while supporting 3SLI, only supports it in x16/x16/x4 mode (all slots 2.0, at least).

This makes me a bit wary of trying a 3SLI arrangement on it (and I won't be be buying a new X58 motherboard for this rig - I am saving up for a megarig based on LGA2011 to be purchased in early 2012). That said, I'll still build the GPUBox, but I am not sure you'll see it in its entire 3SLI glory anytime soon.

 

[heky]

Why did it die? Any chance to just rma the motherboard and continue like planned?

 

[Yukikaze]

Why did it die? Any chance to just rma the motherboard and continue like planned?

The motherboard is out of warranty and I have no idea why it died. I noticed one of my HDDs went MIA and decided to reboot the system to see if it will fix it. When it powered back up it wouldn't work. I tried without HDDs, with every stick of RAM individually, all the usual troubleshooting and nothing worked. I decided to replace the motherboard and voila, everything works now. No idea why it died.

The project will continue as planned anyway - The GPUBox will have room for three GPUs in it, just not sure I'll fill all three slots right away.

 

[[Ion]]

I think it'll still be a cool project, so I'm interested in seeing the result

 

[xbonez]

Sounds great. Definitely awaiting to see the end project. It is slightly expensive to make it a viable solution for most though, considering the price of the extender cables and the requirement of an added PSU.

Btw, you can pick up an EVGA E758 3x SLI motherboard recertified on newegg for 80 bucks, which isn't that much really.

 

[Yukikaze]

Sounds great. Definitely awaiting to see the end project. It is slightly expensive to make it a viable solution for most though, considering the price of the extender cables and the requirement of an added PSU.

You don't need a second PSU - Extender cables for the one you already have will also work. The PCIe cables are quite expensive yes, but this isn't supposed to be a solution for everyone. "Everyone" does not usually run SLI or 3SLI configs

Btw, you can pick up an EVGA E758 3x SLI motherboard recertified on newegg for 80 bucks, which isn't that much really.

If I were in the USA (or anywhere where newegg ships to), I would've grabbed that board in a heartbeat. But alas, I am not

 

[xbonez]

If I were in the USA (or anywhere where newegg ships to), I would've grabbed that board in a heartbeat. But alas, I am not

Ah, yeah...missed seeing your location.

 

[PopcornMachine]

Very interesting stuff. Was looking at PCI-E extenders a while back as I thought they could be used in some crazy case mods.

Hope you resolve your motherboard and other issues.

 

[mATrIxLord]

this looks really cool! sub'ed to see the outcome of this!