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PSU for 20 drives (update the wiki?)

shawn

By shawn
in Hardware

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shawn Apprentice

shawn

Posted
Posted

"20 Drive Beast" recommended Power Supply: CORSAIR CMPSU-450VX

http://lime-technology.com/wiki/index.php?title=Hardware_Compatibility#20_Drive_Beast

 

This PSU has 33A on the 12V rail. Has anyone reported using such a power supply for a 20 drive setup? If we assume 2A per drive spin up then 20 drives would be 40A. The rest of the system uses power too. I would not use this PSU comfortably for such a setup.

 

The following is a report of someone using a 700w PSU with 4 separate 12V rails with 18A each and that failed to power 16 drives:

http://lime-technology.com/forum/index.php?topic=7063.0

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Joe L. Grand Master

Joe L.

Posted
Posted

"20 Drive Beast" recommended Power Supply: CORSAIR CMPSU-450VX

http://lime-technology.com/wiki/index.php?title=Hardware_Compatibility#20_Drive_Beast

 

This PSU has 33A on the 12V rail. Has anyone reported using such a power supply for a 20 drive setup? If we assume 2A per drive spin up then 20 drives would be 40A. The rest of the system uses power too. I would not use this PSU comfortably for such a setup.

 

The following is a report of someone using a 700w PSU with 4 separate 12V rails with 18A each and that failed to power 16 drives:

http://lime-technology.com/forum/index.php?topic=7063.0

I added a note to the wiki.  I agree, the supply is way under-powered for a 20 disk beast.
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Joe L. Grand Master

Joe L.

Posted
Posted

The following is a report of someone using a 700w PSU with 4 separate 12V rails with 18A each and that failed to power 16 drives:

http://lime-technology.com/forum/index.php?topic=7063.0

 

Depends on the PSU, with 4 rails 2 of them are probably for GPU's, which in a system like unraid is useless, thats why a single rail is recommended, so none of the available power is wasted.

See this post for an example of a 4-rail supply I purchased  (it is perfect for my needs, so do not worry. I will not be putting 20 disks on it.)

http://lime-technology.com/forum/index.php?topic=6879.msg66778#msg66778

 

NO RAIL is dedicated to the disk power connectors.  In fact, the disk molex and SATA power connectors share the same 12 volt rail as the 24 pin motherboard power connector.  That rail is rated at 18 Amps, and it is not going to only power the disks.

 

Here is how the cabling is configured between the 4 rails:

 

12V1  

One of the two 4-pin CPU power connectors.

 

12V2

The second of the 4-pin CPU power connectors.

One of the PCIe connectors.

 

12V3

The 20/24 pin Motherboard connector.

All four of the SATA power connectors

All four of the MOLEX power connectors.

 

12V4

The second of the PCIe power connectors.

 

So.... All the disks SHARE the same rail as the Motherboard... and in my case, the 12V4 rail is completely un-used.

 

12V1 and 12V2 are way under-utilized.  

12V4 is completely unused.

12V3 will probably be overloaded if I attempt to put more than 6 or 7 disks on it.  (They say their overcurrent shutdown kicks in at 20.5 Amps)

 

So... do I really have 18 Amps available on the disk connectors... no...  not if the connectors share the rail with the motherboard and all the interface cards and memory plugged into it.

 

 

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Vibe Apprentice

Vibe

Posted
Posted

I was looking at the Corsair 650W for a friend that we have built a Budget Box for (Budget Box #2 under by belt!).  He plans on using this as a file/backup server for a small office environment (2-3 PC's).  He also prefers to use all 7200 RPM hard drives (probably Western Digital Blacks) as he is not concerned with the power saving features of the Green Drives. I know the 20 Drive estimate in this thread takes into consideration Green Drives - However, would the Corsair 650W handle 15 x 7200RPM hard drives?

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Joe L. Grand Master

Joe L.

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Posted

I was looking at the Corsair 650W for a friend that we have built a Budget Box for (Budget Box #2 under by belt!).  He plans on using this as a file/backup server for a small office environment (2-3 PC's).  He also prefers to use all 7200 RPM hard drives (probably Western Digital Blacks) as he is not concerned with the power saving features of the Green Drives. I know the 20 Drive estimate in this thread takes into consideration Green Drives - However, would the Corsair 650W handle 15 x 7200RPM hard drives?

I think so.  It has a single 52 Amp capable rail.  15 drives, at 3 amps each when spinning up would be well within the capacity.
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Vibe Apprentice

Vibe

Posted
Posted
I think so.  It has a single 52 Amp capable rail.   15 drives, at 3 amps each when spinning up would be well within the capacity.

 

Thank you for the reply Joe.  I remember seeing a comparison chart in the forum/wiki for power usage during spin-up (various hard drives) but can't seem to find it now.  I will keep the 3 amp/per drive in mind when my friend purchases his power supply.

 

*Edit - Just found the post...page five of the PSU thread  :)

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Rajahal Mentor

Rajahal

Posted
Posted

Might need to update the projected cost to reflect the up-sized power supply.

 

I'm off my game.  Fixed now.  The total price is actually cheaper now even with the better PSU, I guess since the other components have come down in price.

 

Newegg has also discontinued the Celeron 430, so I changed the vendor to Tiger Direct.

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Rajahal Mentor

Rajahal

Posted
Posted

Not that I know of.  I just noticed that the Newegg link on the wiki led to the deactivated Celeron-D.  Anyone see any reason not to use the Celeron-L instead?  If not then I'll switch the link back to it, since Newegg usually doesn't charge shipping (whereas TigerDirect usually does).

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Kode Enthusiast

Kode

Posted
Posted

The following is a report of someone using a 700w PSU with 4 separate 12V rails with 18A each and that failed to power 16 drives:

http://lime-technology.com/forum/index.php?topic=7063.0

 

Depends on the PSU, with 4 rails 2 of them are probably for GPU's, which in a system like unraid is useless, thats why a single rail is recommended, so none of the available power is wasted.

See this post for an example of a 4-rail supply I purchased  (it is perfect for my needs, so do not worry. I will not be putting 20 disks on it.)

http://lime-technology.com/forum/index.php?topic=6879.msg66778#msg66778

 

NO RAIL is dedicated to the disk power connectors.  In fact, the disk molex and SATA power connectors share the same 12 volt rail as the 24 pin motherboard power connector.  That rail is rated at 18 Amps, and it is not going to only power the disks.

 

 

I'm confused, are you agreeing or disagreeing? Lol.  I'm currently using a 4 rail 700watt FSP Epsilon http://www.fspgroup.co.uk/u.k/02_newproducts/Epsilon.htm but there are only 6 disks attached, at some point I will probably replace it, but its fine for now

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Kode Enthusiast

Kode

Posted
Posted

These any good?

 

 

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Joe L. Grand Master

Joe L.

Posted
Posted

The following is a report of someone using a 700w PSU with 4 separate 12V rails with 18A each and that failed to power 16 drives:

http://lime-technology.com/forum/index.php?topic=7063.0

 

Depends on the PSU, with 4 rails 2 of them are probably for GPU's, which in a system like unraid is useless, thats why a single rail is recommended, so none of the available power is wasted.

See this post for an example of a 4-rail supply I purchased  (it is perfect for my needs, so do not worry. I will not be putting 20 disks on it.)

http://lime-technology.com/forum/index.php?topic=6879.msg66778#msg66778

 

NO RAIL is dedicated to the disk power connectors.  In fact, the disk molex and SATA power connectors share the same 12 volt rail as the 24 pin motherboard power connector.  That rail is rated at 18 Amps, and it is not going to only power the disks.

 

 

I'm confused, are you agreeing or disagreeing? Lol.  I'm currently using a 4 rail 700watt FSP Epsilon http://www.fspgroup.co.uk/u.k/02_newproducts/Epsilon.htm but there are only 6 disks attached, at some point I will probably replace it, but its fine for now

I am stating that many high wattage multi-rail supplies had a completely different target market (those with multiple power hungry PCIe video cards), and most will not be able to handle much more than 6 or 8 disk drives on the one rail they will use for molex and sata connectors.  My example supply shared the rail for the molex and sata connectors with the 24 pin motherboard connector.  I doubt I can use more than 6 drives on it even though it is a 650 watt supply.  (again, it is perfect for my needs, since the server it is going into has a second 300 watt single rail supply dedicated to only powering disks.  Between the two supplies, I have plenty of capacity)
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Joe L. Grand Master

Joe L.

Posted
Posted

Got you, so what you were doing was explaining more clearly why single rail psu's are recommended over multi rail psu's, but also mentioning that multi rail psu's can be used just understand their limitations.

Exactly... and that even though you might have a 700 watt supply, if it has multiple rails you might only have access to 15 Amps or so on the only 12 Volt rail they connected to the molex connectors.  That effectively makes it the equivalent of a 300 Watt single rail supply as far as its capability to power hard disks.
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neilt0 Community Regular

neilt0

Posted
Posted

Got you, so what you were doing was explaining more clearly why single rail psu's are recommended over multi rail psu's, but also mentioning that multi rail psu's can be used just understand their limitations.

Exactly... and that even though you might have a 700 watt supply, if it has multiple rails you might only have access to 15 Amps or so on the only 12 Volt rail they connected to the molex connectors.  That effectively makes it the equivalent of a 300 Watt single rail supply as far as its capability to power hard disks.

 

Exactly. See my post about my second rig for my experience -- my expensive dual rail Antec Phantom 500W does not have enough power on the appropriate rail to power all 14 of my drives (it can do about 7), I had to use a cheapo 300W single rail PSU to power the remaining drives.

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JustinAiken Enthusiast

JustinAiken

Posted
Posted

What about the Seasonic 650W?

 

http://www.newegg.com/Product/Product.aspx?nm_mc=AFC-SlickDeals&cm_mmc=AFC-SlickDeals-_-NA-_-NA-_-NA&Item=N82E16817151088&Tpk=N82E16817151088

 

Thinking of replacing my Corsair 850W (overkill watt-wise, it was on sale when I bought it) with this, because it's fully modular, means I wouldn't have an entire army of useless cables blocking up my airflow...

 

 

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Rajahal Mentor

Rajahal

Posted
Posted

It is a fantastic PSU, but it is a lot more expensive.  Corsairs use Seasonic internals as well, so they are very similar in terms of quality.  If you are looking for a modular PSU then the Seasonic is a great option (Corsair makes a modular model also, for roughly the same price).

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