How many drives can this psu support?  Can it support 5 drives on each of it's 12 volt rails at the same time?

>> +12V1@17A,+12V2@15A

 

I would stick somewhere between 7-9 drives depending on drive models.

I have a Seasonic rated @ 17A on the 12V rail.

I have 8 drives, if I put in a 9th I have intermittent spin up problems every now and then.

I have 3 seagate 7200RPM drives and 5 WD Green drives.

I'm currently running 9 drives on this PSU, split about as evenly as possible.  Most of the drives are green, but I think three of them are 7200 rpm.

 

Keep in mind that this PSU no longer ships with a power cable.  This is supposedly 'good for the environment'.  It is also very annoying.  Considering that it is roughly the same price as the Corsair 400W (which has a single 12+V rail AND comes with a power cable AND has nice cable sleeves), I don't really see much benefit in this PSU anymore.  I only have one because it came with an Antec case I bought a while ago.

Keep in mind that this PSU no longer ships with a power cable.  This is supposedly 'good for the environment'.  It is also very annoying.  Considering that it is roughly the same price as the Corsair 400W (which has a single 12+V rail AND comes with a power cable AND has nice cable sleeves), I don't really see much benefit in this PSU anymore.  I only have one because it came with an Antec case I bought a while ago.

 

+1. Given both can be had for around the same price, people are probably better off getting the Corsair 400CX. At least with that, you don't need to worry about rail balancing.

Is there really a way to balance the 12V rails on this PSU?

 

I've always thought there was one rail dedicated to the motherboard/CPU and another to the peripherals.

 

In fact, I've always thought that was the reason to select a single rail PSU, because you could not manually balance the rails.

I've always thought there was one rail dedicated to the motherboard/CPU and another to the peripherals.

 

That I didn't know. I just figured both rails were available, just going out through different connectors kinda like with the HX520.

 

Searched for the manual and found this:

Connector | 12V rail

20+4 pin main | 1

4+4 pin ATX12V | 2

6 pin PCI-E | 1

4x Molex | 1

5x SATA | 1

1x Floppy | 1

 

I guess that means there's no way to balance this particular PSU. Other multi-rail power supplies I've seen have one of the rails dedicated for graphics/PCI-E connector so you just need a PCI-E to SATA adapter.

so you just need a PCI-E to SATA adapter.

 

I thought the PCIe power connector is missing some voltages (5v??), which means it cannot directly replace a 4 PIN power connector or SATA connector.

 

Am I mistaken?

 

I thought the PCIe power connector is missing some voltages (5v??), which means it cannot directly replace a 4 PIN power connector or SATA connector.

 

Am I mistaken?

 

You know what, you're right. I guess I was still thinking of the HX520 when I posted that. The modular cables are interchangeable for that particular PSU. Not that balancing is required since it all comes from a single 40amp rail anyway.

Mine was pulled from a new Antec machine.  It looks pretty beefy for a 380watt.  Both 12v rails carry 17A.  But does that mean that it's the same 17A shared between them?  They don't both get their own 17A?

 

 5v = 20A

3.3v = 20A

12v1 = 17A

12v2 = 17A

Mine was pulled from a new Antec machine.  It looks pretty beefy for a 380watt.  Both 12v rails carry 17A.  But does that mean that it's the same 17A shared between them?  They don't both get their own 17A?

 

 5v = 20A

3.3v = 20A

12v1 = 17A

12v2 = 17A

 

Max combined load for both 12V rails is 27A. The 17A is just the maximum current you can pull from one rail (probably before over-current protection kicks in). From the manual, the 12V2 rail seems to be dedicated for the CPU so you basically only have 17A to work with.

Mine was pulled from a new Antec machine.  It looks pretty beefy for a 380watt.  Both 12v rails carry 17A.  But does that mean that it's the same 17A shared between them?  They don't both get their own 17A?

 

 5v = 20A

3.3v = 20A

12v1 = 17A

12v2 = 17A

 

Max combined load for both 12V rails is 27A. The 17A is just the maximum current you can pull from one rail (probably before over-current protection kicks in). From the manual, the 12V2 rail seems to be dedicated for the CPU so you basically only have 17A to work with.

 

being an antec, the shunts are almsot certainly NOT going to cut out at 17A, but more like 25-28A which pretty much means you will be able to drawa all your 12v from whatever cable you want to.

Is there really a way to balance the 12V rails on this PSU?

 

I've always thought there was one rail dedicated to the motherboard/CPU and another to the peripherals.

 

In fact, I've always thought that was the reason to select a single rail PSU, because you could not manually balance the rails.

 

Interesting, I didn't know that.  I just split up my hard drives between all the available molex and SATA power connectors and figured I was 'balancing' the load.  Guess it doesn't matter.

 

So does that mean that any PSU with 2x12+V rails should be OK for unRAID?  Or is it only this particular PSU that is configured this way?

being an antec, the shunts are almsot certainly NOT going to cut out at 17A, but more like 25-28A which pretty much means you will be able to drawa all your 12v from whatever cable you want to.

 

Isn't the ATX standard supposed to be 20A?

So does that mean that any PSU with 2x12+V rails should be OK for unRAID?  Or is it only this particular PSU that is configured this way?

 

It's not if the PSU is OK for unRAID, It's if the max amperage on one rail is enough for the maximum drives you want to support at one time during spin up.

 

Keep in mind, An advanced controller can be set for staggered spin up, or you could program your drive with power on in standby (Which is sort of a staggered spin up). Yet the unRAID spinup button does not do staggered spin up.

Therefore you must be prepared for the maximum amperage draw during spin up.