Topic: Regarding risers and PSU cables (Read 3638 times)

Sorry for the late reply - hopefully you've already gotten your answers by now, but just in case...

1. sorry, for some reason I thought I saw 2 perif ports on that PSU - looks like it only has one.  You should have a cable w/ multiple 4 pin peripheral (molex) adapters for that port.  So you'd have to either chain 2 cards on a single perif cable, use one perif and one sata cable (assuming your card pulls less than 4.5A from the risers 12V,) or buy additional PCIE cables.  You can't just use the CPU ports - those are wired differently.  There are converter cables on ebay/amz, though you have to make sure you're getting the ones that are CPU->PCIE, and not just PCIE extenders (double check the wiring yourself - I've read reviews that make it sound like the wrong item gets shipped sometimes.)

2. Nothing wrong w/ using all 8+6 cables - def the safest option, assuming you're under ~225W per card.  You can't purchase individual cables from EVGA - they only sell bundles, which are ridiculously expensive and you get a bunch of crap you don't need.  You can get aftermarket ones from places like moddiy or cablemods (https://store.cablemod.com/configurator/)  Generally, you can't get these from amzn, as the supply side termination is unique to the PSU manufacturer.

You are the best ! thank you.

I run several 4 x RX 570 rigs on 750W Gold PSU's, so 650w is more than enough for your need. Superflower makes some very good PSUs, and Antec is decent in the gold and above category so either of them will be suitable.

Hi Deadsix,

I'm wondering if i could call on your knowledge once again.

Do you think it's possible to power a headless rig; 1x RX580 GPU, 1x Mobo/CPU/Ram/SSD, 1x Ver. 8s Riser by a Gold Standard 650W PSU. There are two local options for the 650W PSU in Superflower and Antec. Antec is about $30 cheaper than the Superflower.

Im thinking 250W for combined (SSD,Mobo,CPU,RAM) and 150-170W for GPU/Riser ? = 400-420W. Which is approx 64% of the 650W load of the PSU.

This should be more than ok, right ?

The other GPU's and risers are powered by a Server PSU.

Thank you so much for this. I will lose both those SATA to Molex adapters and either buy some of those 8s risers which have SATA, Molex and 6 Pin connectors. Then decide to either go with the SATA connection or use the Splitter and the 6 PIN connection.

Many thanks again.

Thanks for this useful information.

I have been using Sata cables to power my risers and did burn one sata / molex cable converter a while back.

I will re-configure my rigs now after reading this.

Thanks again.

Just a quick one on this maths. I was wondering whether to use a sata cable for a single riser, or split a pcie cable between two risers on a rig. Kinda concluded that it would be worse to split the pcie cable, as pcie max 75w, divided by 2 risers is 37.5w - less than sata @54w max...?

(Sata max 54w: http://www.playtool.com/pages/psuconnectors/connectors.html)

Using Sata cables with the sata-molex adapters to power the motherboard is perfectly safe, the motherboard doesent use any power from them if you are using powered GPU risers, which in your case you are. You dont need to have those AUXPWR ports plugged in at all.
Sata to molex adapters should be avoided for powering risers (can be used with nvidia cards, not with amd). If you only have sata cables, and need to power risers, then buy the sata power type risers.
As for the 8pin-2x6 splitters, those are pretty safe always.

There is so much great info on this thread. I have tried searching for some answers but I have come up empty handed.

My setup;

6 x MSI RX 580 8gb.
Biostar 250 BTC PRO
Version 6/7 Riser (Only Molex Connection).
Gigabyte 1200XP – don’t give enough cables and don’t sell individual cables.

I am about to introduce another 6 GPU’s to this setup with another PSU.

PROBLEM: Setting up the first 6 GPU’s with risers, I used all the molex cables and was left with only some 6 PIN to 4xSATA cables. So, when it came to powering the two 4 PIN AUXPWR ports on the Mobo, all I could use was a single 6 PIN to 4xSATA cable then use SATA to molex adapters to plug into each of the two AUXPWR ports.

On a scale of severity, how bad is that?

Those adapters always feel cool though.

If I can find a website/service to make some more molex cables for me that work with this particular PSU, is it still possible to use one single cable to power both AUXPWR ports?

Last question, there is allot of warnings about Molex to SATA adapters and to not use them with risers. Does that go for SATA to Molex as well, or all adapters that are sold ? i have a splitter; 8 PIN female that splits to 2x6+2. Are these a risk as well?

They are asus strix, they're coming in this morning I hope. If that's the input then I can only connect 4 1080 to that psu, having 8 pcie outputs?

which 1080ti do you have?

I thought they all have 2x8pin power connectors?

My graphics cards take two PCIE connectors each and draw a lot of current.  I'm not sure it would be advisable to use a splitter and have that one cable provide all the power for both the GPU and the riser.

If I can use molex I will use that over sata.

Hi all, i'm building a 6x1080ti rig for the first time and got some panic with all the sata risers stuff to be honest. I've been reading this post and like 1389349539 more but still can't think clearly what should I do, and that's why I ask for some help here, would appreciate it a lot.

As i said, its 6x 1080 ti and I assume will be underpowering them to more or less between 150 and 180W. Got the corsair ax1600i (http://www.corsair.com/en-eu/ax1600i-digital-atx-power-supply-1600-watt-fully-modular-psu-ww) and also my risers have only 6pin power connections.

- Can i use each PSU PCIe connectors to 1GPU + 1 riser, using a split cable (i believe 8pin to 2x 6pin splitter)? Is that safe/capable of providing the gpu+riser the W they need?
- Should i use 1 PCIe to 1 GPU and the other 2 PCIe for 3 risers each?
- Any other better combination/s?
- Not any of what i said... 

Thank you very much in advance

Thanks a lot for the detailed reply - I learned quite a bit from it, and have ordered the 008 risers as per your recommendation!

Two follow-up queries:

• You mentioned I could use 2 x 4 peripheral cables (molex) to power the other two risers (ones which aren't connected using risers). Did you mean that I use each of the 8 pin CPU ports in my PSU (marked as CPU1 and CPU2) for 2 molex cables (referring to the back of my PSU whose pic I've linked before)? If not, I don't see any more ports that are capable of handling the 4 pin Molex's? 
• I'm trying to get identical power inputs for each of my GPUs - so, I'm considering buying 2 more Y splitters ( 8 + 6 split(Y) to 8 pin) so that each of my 4 GPUS and its corresponding risers are powered using the Y cables. Is there anything wrong with that idea, other than the fact I'll have to order extra splitters? Speaking of which, I should be able to purchase EVGA splitters from the manufacturer's website, right, or would any amazon Y splitter would do?

Thanks!

A cable w/ an 8 pin termination should be able to supply 150W according to the PCIE spec - if your GPU is drawing less than 150W, you should be able to split such a cable between the GPU and riser.  The better option would be to simply use an 8+6 split (Y) cable - 8 pin to the GPU, and 6 pin (w/ an extender if necessary) to power the riser.  That way you can be certain the cable is rated for that load (an 8 + 6 termination should supply 150W + 75W per PCIE spec,) assuming your cards draw less than 225W (which they absolutely should for mining.)  Since you only get two of those types of cables w/ your chosen PSU, you could use the 2 x 4 pin peripheral (a.k.a. molex) cables to power your other 2 risers.

A couple other notes:

1. The draw on an 8 pin termination of a PCIE cable is spec'd to 150W, but the cable likely can provide closer to 180W (3 hot pins @ 5a x 12v or 60W each,) while the supply is actually probably closer to 240W (4 hots x 60W,) so you're probably fine just splitting a single 8 pin terminated cable if GPU TDP is < 180W.  But if you want safest, the config above works (and saves you from buying additional splitters.)

2. The FUD around sata power is a little overblown.  While a sata power connector easily provides the 75W max allowed for a PCIE x16 connector, the main concern is that the PCIE spec allows for 5.5a over the 12v rail (66W) on the MB connnector, while a sata power cable only provides 3 12v pins @ 1.5a each, or 12v @ 4.5a (54W) total.  However, most modern, optimally tuned GPUs run around 75-150W for mining, so a single 8 pin PCIE power cable likely provides all the 12v power the card needs, w/ the MB connector/riser providing the 5v, and minimal (if any) 12v.  Of course, this split is up to the GPU manufacturers, and they *could* technically pull all available (66W) 12v power from the MB bus before utilizing the PCIE power cable (or split as evenly as possible across the 2 sources,) but that is not how I've seen power delivery implemented on any recent card I've used.  My cards all run in the 100-150W range, and the ones using risers powered by sata cables are doing just fine.

3. Ver 006C is pretty old for the risers.  I would recommend at least ver 008s, like these: https://www.amazon.com/EXPLOMOS-Graphics-Extension-Ethereum-Capacitors/dp/B074Z754LT

I'm a new comer to the forum, and I'm trying to get one last bit of info before I can assemble my 8 GPU rig. I was hoping you could answer my query regarding a similar setup.

I'm planning a 8 GPU build, in which I've ordered the following components:

• 2 x EVGA SuperNOVA 850 Titanium PSU
• 8 x GTX 1070 Founders Edition
• Risers (6 Pin 006c as recommended in the wiki https://www.reddit.com/r/EtherMining/wiki/hardware/risers)

Here's a pic of the connections available in my PSU: https://imgur.com/a/j5TII

What I'm confused about is which slots do I connect the risers? I feel I have the following options:
1) Use a PCI-E splitter, so that each VGA slot is used by 1 GPU and its riser (got the idea from your aforementioned post)
2) Put each GPU in its own VGA slot, and its corresponding riser in a 6 pin slot in the same PSU (will have to use up a VGA slot for the third GPU)

Option 2 limits me to 6 GPUs in this rig, though my mobo is capable of 8 (z370-A). I'd obviously like to have a 8 GPU setup, but I don't want to use an option that is remotely unsafe. Am I being too paranoid about the whole thing (u can tell I read the Risers section in the wiki quite a few times!) ?

Right, I'll only be able to do 2+2+1+1 in that case since I have two molex cables left over that I don't use from my PSU that I have on my gaming PC. I'm assuming they'll work since the two PSU's are the same model but different wattage. One is EVGA G2 750 and the other (for the mining rig) is EVGA G2 1300.

My suggestion is use as many PSU peripheral cables as you have. If you have enough to do 1 per, do that. If you can do 2x2 +1 + 1, then do that.

I understand that it's safer to go with the 6-pin risers. I'll order those. However, I have molex risers incoming already - which I always thought as temporary because I could get them fast. Question is if I can use them for a week.

I've read that three risers per cable will melt it when it comes to molex. That's why I was thinking two risers per cable and three cables.

You say that some cables melted when the room was hot enough - can you remember how hot the rooms was when they melted - or take a guess at least?


Now, I don't know much about electricity but pretty much everyone who has an AsRock BTC motherboard and use the two molex connectors on the motherboard claims that it works absolutely fine with all six GPU's and unpowered risers. I don't doubt you (I'll order the 6-pin risers to be safe!), but it seems to me that only two molex connectors on the motherboard nets you another max 100W, but that's apparently still enough for six GPU's on that motherboard. Or am I missing something?

these cable are my enermax PSU's molex (PSU's endpoint) , ran 2 riser for each cable


if I use 2x Molex to PCIe converter to powerup PCIE 6 pin riser


never use molex to sata converter