GPU array

[ayu]

I have decided that I want to build some sort of GPU array for hash cracking, for 100% legal purposes of course

I have not decided how the array should be built yet as I haven't done something like this before (more than having 2-3 graphic cards in the same machine, bridged).
I have some ideas though of how I would want it to work, but I'm not sure if it could really work.

One idea is to have some sort of controller card where you would mount X number of graphic cards, and then connect them to whatever power source.
The controller card would then be connected to a computer via USB or such so that it could then be used by an application like oclHashcat on the machine.

Another idea is to just put a bunch of graphic cards into a computer and bridge then like normal.
The problem I have with this idea is that it would limit the amount of cards greatly since I would need to have a huge computer case.
I would much rather have them seperately somehow.

Is there some kind of setup like this that I could use?
Any ideas?

[bad_brain]

well, the USB solution would not work I think, simply because I doubt you can suck the power needed for multiple g-cards through USB, it's simply not made for that.

but there is a pretty easy solution actually: riser cards. have a look here, just as example:
http://www.plinkusa.net/riser.htm" onclick="window.open(this.href);return false;
that way you could extend a single PCIe port for use with multiple cards...

[ayu]

ah thanks b_b, it was something like that I was after

Will check it out!

[reparto]

An alternative yet useless solution is to use a USB3-PCIe enclosure, you could probably fit 2-3 gpu inside them but they require driver compatibility which will be the main issue

[ayu]

An alternative yet useless solution is to use a USB3-PCIe enclosure, you could probably fit 2-3 gpu inside them but they require driver compatibility which will be the main issue

hmm ok, but I guess it's as b_b said about that, that USB wont cut it

also, b_b, I checked out the riser solution and a friend says that it wont work, since one card needs all channels dedicated to itself.
Comment on that?

[bad_brain]

well, you could use an external powered USB port, like it's done with many USB hubs....of course you would need a decent power supply, best a regular PSU...would be the easiest.

about the channels....hmmm....I am not sure about this, I actually don't think so, because IRQ sharing is possible (worked already in Win 2000 days, so modern BIOSs/OSs should also definitely support it). and since the g-cards will have no actual output (graphics I mean) and only do their work internally through the GPU the port bandwidth limitation should also be no problem. of course this is all just my theory because of a lack of IRL experience...

[reparto]

hmm ok, but I guess it's as b_b said about that, that USB wont cut it

also, b_b, I checked out the riser solution and a friend says that it wont work, since one card needs all channels dedicated to itself.
Comment on that?

Sorry I meant thunderbolt
http://www.magma.com/expressbox-3t" onclick="window.open(this.href);return false;

It has a separate PSU

Also, you shouldn't need all the PCIe lanes for hash cracking, i have seen a few mining rigs setup with 1x risers

[ayu]

Guess I will have to do some reasearch about this.
If anyone of you can give me some proof or material that can show a build that is actually using risers with graphic cards for something like this, then that would be awesome

The search continues ^^
I have currently ordered a HD7970 card to start with, as my server has 2 PCI-E slots available.

[bad_brain]

ok, I have looked around a bit, what you need to be on the safe side is "active" riser cards, those provide an own IRQ for each new slot...from what I have read most of the super-weirdo graphics benchmark results have been done that way, so it's more or less widely used.
if you have some extra bucks left and want to get the best results possible without having to fiddle around with 3rd party hardware solutions you can get this badboy here:
http://www.asus.com/Motherboards/P6T7_WS_SuperComputer/" onclick="window.open(this.href);return false;
that mainboard was used to build the FASTRA 2 system:
[youtube][/youtube]

[reparto]

Guess I will have to do some reasearch about this.
If anyone of you can give me some proof or material that can show a build that is actually using risers with graphic cards for something like this, then that would be awesome

The search continues ^^
I have currently ordered a HD7970 card to start with, as my server has 2 PCI-E slots available.

Well... you only need 16 lanes if you need to saturate the 12GB/s bandwidth between the CPU and GPU (12GB/s on PCIe 3), seeing as though hash cracking is like bitcoin mining, you should be fine with 1x PCIe 3 (~1GB/s)

https://forum.litecoin.net/index.php/to ... l#msg13414" onclick="window.open(this.href);return false;

Also, all the bitcoin stores sell 1x - 16x risers