help with multi gpu expansion rig?

[petermax]

hi there,

I bought several gpus, have 4 now, gtx 570 and 580s only to find out that although my computer has 3 slots it can only fit 2, because all the gtx 580s are oversized

What is the most simple way of adding the additional cards to my current rig, without buying a second rig, because I want them to compute all at the same time? I have the cards and PSU, can I run a few more cards externally?

Does anyone have experience with this and give my ideas? point me in the right direction?

thanks in advance

does anyone know where I can get something like this made?



that looks like it's running via a separate motherboard, can I run something like this externally directly via a link to my current motherboard instead?

[mib2berlin]

Hi, there are some threads about expansion rigs, here is one of them:

http://render.otoy.com/forum/viewtopic.php?f=11&t=20949

Here, googled for gpu expansion cable:

http://www.cyclone.com/products/expansi ... 0-2710.php

http://linitx.com/viewproduct.php?prodid=10881

The expansion rigs are very expensive, 1200-2000 €.
There are some mainboards with 4-7 PCIe slots but for xeon CPU.

http://www.supermicro.com/products/nfo/GPU.cfm#GPU_Mobo

Cheers, mib.

[glimpse]

if You have available slots, but no space because cards are too big =) use raisers.. siple flexible cables and mod Your case.

Expanders are crazy expensive, so even buying new rig or upgrading the one You have is much more economic =)

[petergazo]

If you aleready have motherboard with enough slots and capable PSU, buying new bigtower case would be cheapest solution. Even $100 case like Corsair 500r or can cool 3-4 cards. Just install two additional 140mm side intake fans (default 200mm fan is useless). One note, some bigger motherboards will fit into case but theres litlle space where SATA cables should be installed on mobo might be problem if you have more than 3-4 disks.

Theres plenty of other case options, i just wanted to point one cheap which works for me.

[petermax]

Thanks for the input!
I don't want to buy one of those gpu expanders, they seem like too little value for money.

The riser card option sounds like the way to go. Well I have about 6 slots, but if I'm not mistaken I can only use 3 of those right? The gtx 580 I have only use 1 slot but seem to occupy 2 slots.
So I could connect 1 more card with a riser. Is it a problem if I run this card via a separate PSU? because my current one will only support 2 cards, but I just bought another 1200w PSU.

The second case sounds like an interesting idea, actually I have a spare cases I could use, but how would I connect the two? I would like to run them all at the same time and keep loading geometry time to a minimum.

[FooZe]

Hi petermax,

What you need to check for on your motherboard is the number of PCIe x16 slots. These are usually longer than standard PCIe slots and have a latch at the end of them to hold the card in.
Usually the x16 PCIe slots are placed 2 slots apart on the motherboard for the specific reason that GPU's are 2 slots wide! I would be very surprised if your motherboard had 6 PCIe x16 slots!
Motherboards that can take more than one GPU are commonly branded as Nvidia SLI capable. (either 2-way, 3-way or 4-way; 2,3 and 4 GPU's).

I would be very hesitant to run some cards off a separate PSU without some good research on it. I have heard that this is not a good idea and if you are going to do this then some re-wiring is needed to keep all the PSU's grounds linked. I'm not an electrical engineer so i don't know how much this is actually true, but i would be cautious and look it up. The other problem you may come across is switching, how to turn both PSU's on. I'm guessing if you have another case you can use this power button and perhaps this will work, turning on the GPU first before the main system. I have spent some years supporting hardware and i can't say i'd be entirely comfortable with a setup like this even if it did work! So no recommendations here!

Cheers
Chris.

[petermax]

right well in that case I've got a 3-way SLI case, if I could squeeze in a the third card, I'd be more than happy
might have to somehow replace the old PSU with my 1200w one, I was hoping i wouldn't have rip out the old PSU