Ghetto build

[super gnu]

agh! i just saw the link to the risers youve ordered.. those are 1x pcie risers!!! dont get them!! they have a slot for a 16x card, but they connect to the motherboard with a widdly little 1x connector. itll work, but your data transfer rates to the gpus will be awful. mining setups dont need high bandwith so they are fine for that use.

you need a full 16x riser..

like this for example:

https://www.overclockers.co.uk/ocuk-...cm-14e-ok.html

or this, for a longer (and more expensive one)

https://www.amazon.com/EZDIY-Express...QT0E40V60&th=1

[JezUK]

agh! i just saw the link to the risers youve ordered.. those are 1x pcie risers!!! dont get them!! they have a slot for a 16x card, but they connect to the motherboard with a widdly little 1x connector. itll work, but your data transfer rates to the gpus will be awful. mining setups dont need high bandwith so they are fine for that use.

you need a full 16x riser..

like this for example:

https://www.overclockers.co.uk/ocuk-...cm-14e-ok.html

or this, for a longer (and more expensive one)

https://www.amazon.com/EZDIY-Express...QT0E40V60&th=1

Thanks Super Gnu,

I managed to cancel the order of those Risers and the Aluminium Frame I'd designed and went back to the drawing board.....

I've since learned that the Riser Cable you pointed me towards has a limit of 300mm in length - so I've redesigned the open-rig frame once more;

I have also decided to get that 2nd PSU, and my plan is to have 2 x 1500w for the GPUs (4 and 3), and my spare 760w just for the CPU and hard disks and ram.

Would it be okay to have the GPUs resting on angle plates at each end ? Or would it be best to screw the GPU's in (as you'd do when mounting to a case) ?

PS - this cost of building an open-rig soon mounts up.......

[super gnu]

id have the top of the riser screwed to a bar (they have holes for this, check the pictures) .. that way the bottom of the gpu will be held in place.. then have another bar horizontally across the back that the gpu bracket can screw to at the top, like it does in a case.. id never leave a gpu just "resting".. especially since most gpus have the rear of the circuit board exposed.. short circuit!

also they dump a fair amout of heat out of the backs of the cards, you want airflow across there too.

finally, id design to keep the risers as short as possible.. ive read that pcie doesnt really appreciate being "risen" too far.. the extra cable length picks up interference. hence the upper limit on riser length.

you could be clever and shield the risers with tinfoil /aluminium tape, and earth that.. it should improve stability on long lengths.. also, check reviews before buying.. there seem to be some pretty crappy risers for sale.


man i miss doing stuff like this.. ive not had the cash for quite a while to splurge on a custom build.

[JezUK]

For some reason I couldn't upload my two pics......

I think the angle plate would be totally fine - there's nothing there on my cards and the angle plate is only an inch deep - I'd protect them by using rubber mats to avoid metal to metal contacts.

(I have to say, designing this has given me a few headaches !).

[JezUK]

id have the top of the riser screwed to a bar (they have holes for this, check the pictures) .. that way the bottom of the gpu will be held in place.. ... ..

Thanks again - I didn't see that they had holes for mounting screws.....

It wouldn't take too much modifying my current design to accommodate those bars to fix the riser female end and be doing away with those angle plates I chose......

Dang, this is about the 8th design iteration !!!! (and my head started hurting after the 2nd.....)

[JezUK]

What do you think of these Riser Cables ? (though I'm not completely convinced those holes mightn't cause some kind of shorting.....)

[JezUK]

Hey Jez.

Yes, I power the 5 GPUs via their psu's first, then power the main mb psu (and other 2 gpu's) last to power everything up. All gpu's need to be powered before the mb bios turns on so they can all be detected by the bios. If you do it any different, the bios might turn on first and not see some gpus and those gpus will not be detected by the bios and or windows.

My power supplies came with a free self test thing that allows one to test the psu before connecting it to the computer to see if it works or is a dead psu.

https://linustechtips.com/main/topic...-power-supply/

...it goes on the mb connector and is simply a jumper wire connecting a couple prongs on the connector telling the psu to turn on and supply power. Once the self test tool is connected, you switch the psu on, and the psu turns on (supplying power to the rails or cables). I leave my tester tool plugged into my psu all the time and leave my psu's switched on all the time. That way I don't have to switch on the 2 psus that power the 5 gpus each time I turn the computer on.

The gpus don't pull power when the mb psu is turned off...basically everything is off, just like the main psu, when the computer is off.

The kill-a-watt meter is currently not plugged into anything. I only plug it in when I need to take a wattage/amper reading. Then I leave it unplugged. I only used the meter briefly to see how much wattage the two psu's that powered the 5 gpus were using when the computer was off and the psu's were switched on with the seft test thing plugged in...it was like 75watts or something really low, so I just leave those psu's on all the time with the self tester tool plugged into each.

Let me know if you still have any questions...hopefully this helped.

Thanks Bio, that helped a HUGE amount - I will most likely do the same - although my PSUs are very new, I too would prefer leaving them on all the time and that way just switch on the mb as 'normal'.

I've now been advised to go for the ribbon riser cable rather than the ones I'd originally chosen - the risers I had ordered only work at x1 and not x16, but you're right, had I been using those, I would have needed power and would have gotten that from the MB PSU.

The riser cables I'm now looking at ordering do not seem to have any power requirement though....

Thanks for all your help

[super gnu]

well i offer no guarantees as to the quality of the risers, they are expensive, and have 5 good reviews, so.. seems a reasonable bet. the screwholes for mounting the riser to a bar look very flimsy, but i guess if you are careful with them...

youll also need some small cylidrical spacers on the screws to hold the riser away from the bar slightly.. you risk squashing whatever is on the side of the riser socket when you tighten the screws otherwise.

[super gnu]

loooking at your design there.. if the motherboard is mounted in the top right, as it seems to be, will a 30cm riser be enough to arrive at where the bottom gpu is located? id imagine youll need the motherboard mounted centrally on the vertical, with the cards equally distant from the top and bottom of the pcie slot area.. does that make sense?

[super gnu]

if you need a longer riser you could always chuck a few of these in

http://www.maxexpansion.com/kits/pcie3-x16-host-target

[biochemical_animations]

Dang, this is about the 8th design iteration !!!! (and my head started hurting after the 2nd.....)

Tell me about it...I did about a month of research before jumping in.

[biochemical_animations]

What do you think of these Riser Cables ? (though I'm not completely convinced those holes mightn't cause some kind of shorting.....)

I've read it's best to go with powered risers...see my previous link to the 8x to 16x powered riser from moddiy...that's what I ran and they run great.

[JezUK]

loooking at your design there.. if the motherboard is mounted in the top right, as it seems to be, will a 30cm riser be enough to arrive at where the bottom gpu is located? id imagine youll need the motherboard mounted centrally on the vertical, with the cards equally distant from the top and bottom of the pcie slot area.. does that make sense?

No, the mb and components stay inside my existing case. Only the 4 gpus I currently have which are squashed into my PC case are what I want out of the case and onto a frame. The rest of the mb and components will stay in my existing case.

My current case is a Vengeance C70 which has a side window that I can remove and pass these riser cables through.

Here are some more pics of my design (all obviously to scale and laid out as I need them to be) - I refined my design even further as I noticed I had some tubes I could get rid of.......

The 3rd picture shows how I (so far) intend mounting the gpus - with screws on one end and rubber protected angle plate on the other end. I know you mentioned about shorting and obscuring heat etc but I really don't think that'd be an issue. There is nothing on that side at all (it's just the plastic outer casing of the card)

As you can see I've also put 4 x 120mm fans that side too.

The lime boxes are obviously PSU's (please excuse the lack of photo-realism )

[JezUK]

if you need a longer riser you could always chuck a few of these in

http://www.maxexpansion.com/kits/pcie3-x16-host-target

Yeah, I'll take 7 of these

[super gnu]

ahh isnt it nice being able to design stuff in 3dsmax.. every time i have to build something its straight on me computer. i notice you textured the graphics cards.. as i would have done.

edit: yeah your design looks fine as long as the risers will reach.. you should draw them with splines and check spline length.

i was imagining the cards resting on the back face where the exposed circuitry is.. that would be a problem.. your layout is fine tho.. like you say, its just resting n the plastic shroud.


edit 2: couldnt you squeeze it down smaller? im sure you could reduce the space between cards and have it 3 fans high instead of 4