Topic: V007s SATA powered risers (Read 4077 times)

Sorry, was reading the thread and wanted to clarify couple of points:


Did it ever melt for anyone, or community is just theorizing on SATA specs. I've read about fried MOLEX connectors and melted SATA/MOLEX adapters,  but haven't encountered any reports about burnt SATA risers.


But can a video card actually request more current than mediator device (riser in this case) can handle? Not that good at physics, doesn't it work the same way as a network bandwidth - so if cable/switch cannot put through more than 100 mbps, devices on both sides of the network simply won't be able to push through something bigger?

Same with T2 series. Running 2x EVGA 750W T2s.

EVGA G2? Yep, the sockets are the same other than labels.
Seems to be common for EVGA PSUs, I've noticed it with G1, G2, GS and PS series. (all of which conveniently use the same modular molex cable pinout)

So I can use the Perif - Molex cable in the SATA plugs on the PSU as well?

that entirely depends on which cards you're using, while most don't draw over 20w from the PCI-e slot, there have been some oddballs even breaking the 75w limit

Correct. My 750w G2 are setup similar to your PSU2 above, CPU to 2x 6pin splitter and using 1 molex string per riser.
(I had spare EVGA G2 molex cables, and on the PSU side PERIF/SATA sockets are wired the same)

As I keep saying, sata works fine for most people. It's very unlikely it will catch fire and melt.  BUT the undisputed fact remains that the spec only requires that it be able to cope with a maximum of 4.5 amps on the 12 volt pins.  Good quality ones may be able to handle more - depends on the quality of the connector.

The following refers to 12 volts:

1. The PCIE spec dictates the slot must be able to sink a maximum of 6.25 amps.

2. SATA spec dictates the connector must be able to handle up to 4.5 amps.

3. Molex spec dictates the connector must be able to handle up to 11 amps.

The more current, the more voltage drop and the higher amount of heat generated.  If your card is drawing less than 4.5 amps then there is no risk,  Many if not most cards will draw less than the maximum from the slot.  However, if you have one of those 250 watt beasts, it is likely it will draw more than 4.5 amps and up to 6.25 amps.  Which will exceed the design specification of the sata (but be well within the abilities of the Molex).

Exceeding the amount of current the connector is designed to handle, will not automatically mean fire and disaster.  But it certainly increases the risk.  Most power supplies have heaps of spare sata and not enough molex or 6 pin.  That is the main reason it gets used.  In most cases it works fine without melting. But it would be better to spend a bit more on a good quality power supply that can handle at least 50% more than your calculated usage.  Power supplies are generally more efficient when used at 50 to 70% capacity and the larger size will likely mean more molex and 6 pin connectors.  Yes you can use sata to power your risers, and most likely nothing bad will happen, but it's definitely more risky than using molex or 6 pin.

It's ok to split one wire to power 2 risers.  As in using 2 molex.  Or even 2 sata if your cards don't draw too much current.  The limitation here is more to do with the wire size.  18 AWG is generally used for sata and molex and over the distances involved it can cope with the current from 2 cards, but 3 or more is pushing it and will likely result in the wire getting warm.  Depending of course on the cards used.

If you really want to be safe and operate your rig within specs, I suggest the following:

1. Do not use sata for anything related to your GPUs.

2. Split a molex or 6 pin into no more than 2.

3. If you don't have enough connectors, buy a bigger power supply that does.

Yeah of course you can use sata and you can split your wires into 3 or more and no it probably won't end in disaster.  But it is certainly more likely to than if you were keeping within specifications.

O.M.G. That. That is exactly what I was confused about. And it's sitting right under my nose.

So given I want to run 7 cards on one mobo, and I have 8 PCI-E (VGA) cables amongst 2 PSUs.

PSU 1
Mobo + CPU
GPU1: VGA1 + Perif-1 to Molex string (1 of 4)
GPU2: VGA2 + Perif-1 to Molex string (2 of 4)
GPU3: VGA3 + VGA4 (to 6-pin riser)

PSU 2
GPU4: VGA5 + Perif-2 to Molex string (1 of 4)
GPU5: VGA6 + Perif-2 to Molex string (2 of 4)
GPU6: VGA6 + CPU to 6/8 splitter (OR buy a 8pin to 8pin PCI splitter for both)
GPU7: VGA8 + CPU to 6/8 splitter (OR buy a 8pin to 8pin PCI splitter for both)

Is that right? That makes so much more sense now...!

never use any sata connector in mining rig

Okay, there's a terminology problem here.

When we say 6-pin or 8-pin, we mean the 6/8 pin PCI-E power cables. EVGA G2 750w has four.


Basically, you could use a 8pin PCI-E splitter and connect it to both the RX GPU and direct to the riser's 6 pin socket.
Alternately, it's possible to get (or make) cables that convert the PSU's second CPU EPS12V 8pin connector into a pair of 6/8pin PCI-E and use them to power a pair of risers.
Example:
http://www.ebay.com/itm/CPU-8Pin-to-Graphics-Video-Card-Double-PCI-E-PCIe-Power-Supply-Splitter-Cable-/272720358725

Or.... for the risers with the direct molex connection, you could obtain more EVGA G2 compatible molex cables, as for an EVGA G2 all the SATA/PERF sockets on the back of PSU are wired identical/interchangable. (EVGA G2, G1 and GS all use the same pinout for the molex cable)

I don't think I have ANY 6pin / that the problem. I have sata 6-pin with four flat sata connectors on one string and then perif 6-pin with 4 molex string.

No 6-pin to 6-pin cables. This is the problem.

I hear ya. But then I've also seen the burned melted data connectors so so not sure what to think.

Of course it does.
So it does on hundreds of rigs.
The amount of FUD regarding sata risers is too much.

Using v007s. Works fine on me

http://imgur.com/XapyNZ0

If you don't have enough 6 pin PCIE buy splitter
https://www.amazon.com/PCI-Express-Y-Splitter-Adapter-Converter-Gaming/dp/B004PBJARO
I've bought them here in CZ, one for 4 bucks. I think the brand was Delock.

I have one perif plug on my PSU. And 4 SATA plugs.

So you're saying to ignore the SATA plugs entirely. And only use the Perif 6-pin plug? And if in that case, the most I can get out of that 750W PSU is two (MAYBE) three molex connections (on the string of 4)

If I was going to use the risers with 6-pin, what exactly is the cable I need and is it a 6-pin perif cable or a 6-pin sata cable (I'm talking about the labels on the PSU)

I have two EVGA 750W.

Any links to the actual cable would be super helpful...

According to the sata spec, the 12 volt pins are rated for 54 watts as the maximum.  As in 1.5 amps for each 12 volt pin, of which there are 3.  Yeah it will most likely work even a bit over that if they're good quality.  But it's better to use molex or 6 pin which are rated to handle considerably more current.  Just to be on the safe side.

3 risers on SATA works fine as well (Corsair). 4 doesn't work, will give issues with cards.

Use 8 or 6 pin splitter, those cables are made to be full powered.
As I wrote 8 pin can handle 150W so you can use 1x 8pin to 1x 6 pin on riser (75W) and 1x 6pin on card (75W), There should be no problem with 8 pin card either...
I wouldn't go for the Sata and definitly not for those SATA adapters! They are very low cost and bad quality.
I tried 3 risers on 1 molex rail and it was no problem at all, Corsair HX1200 has quality cables they were only around 30° (IR thermometer).

No, you need to buy a proper power supply so you dont burn your house down.