j5428 Posted February 23, 2008 Share Posted February 23, 2008 How many hard drives can be run from an Antec Earthwatts 500w power supply? Does anyone here have one of these running a ton of drives? Quote Link to comment
Joe L. Posted February 23, 2008 Share Posted February 23, 2008 The antec web-site says: Dual 12V outputs: 12V2 for Motherboard and peripherals; 12V1 for processor and +12V1 = 17.0A +12V2 = 17.0A So, you only have 17 amps for the hard disks. It is considered far better to have a single large capacity 12 volt output rather than dual 12 volt outputs, since with dual outputs, only half of the capacity is available for the disks. You really have a 12*17 = 204 watt supply for the disks. It is a high efficiency power supply, so that is a good thing... To answer your question, about 1/2 the drives you could power from a 500 watt supply with a single 12 volt 34 amp output. However, to complicate things... such a huge single rail output has its own issues for safety... Check out this link for an education in how power supply rails are used, abused, and marketed. http://www.playtool.com/pages/psumultirail/multirails.html Joe L. Quote Link to comment
JRS Posted February 23, 2008 Share Posted February 23, 2008 Allow me to muddy up the waters a bit... One unRaid user on this forum mentioned running 10 drives on an Antec earthwatts 380 without any issues. Using a general ratio then, a 500 would then handle at least 13 drives. On more than one occassion I've read that the Antec earthwatts are really single rails PSU's. Here is the closest reputable source to I've found to support this: johnnyguru's review: http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=35 A quote from that review: "I plugged in the 8-pin EPS12V connector and proceeded to put a 30A load on it. The PSU did not shut off, which confirmed that my visual observation that all of the +12V leads were in fact coming from the same source on the PCB. The Antec EarthWatts does NOT have multiple +12V rails. It only has one +12V rail with no limiters on any of the connectors." I have no idea if that is a valid test - load up a "multiple" rail CPU's single rail and if it works, than it really is a single rail. Quote Link to comment
Joe L. Posted February 23, 2008 Share Posted February 23, 2008 And to quote from the link I gave All this adds up to the suspicion that many power supplies which claim to have multiple 12 volt rails are actually single 12 PSUs despite how they're marketed. It's clearly a fact according to Intel's testing that many PSUs can deliver far more current on a single 12 volt rail than their specifications claim and even more than the 20 amp limit. It's understandable that PSU makers would continue to market them as multi 12 volt rail PSUs since many people think that multi 12 volt rail PSUs are superior to single 12 volt rail PSUs. You might be better off than I originally described (if it really is a single rail supply) , if the marketing folks got in between the engineering team and the lawyers. Quote Link to comment
bubbaQ Posted February 23, 2008 Share Posted February 23, 2008 Depends on how much juice the drives pull, staggered start, etc. Quote Link to comment
Aaron Oz Posted February 23, 2008 Share Posted February 23, 2008 I have 10 drives running just fine off of a crappy Rosewill 350 watt PS. Quote Link to comment
j5428 Posted February 23, 2008 Author Share Posted February 23, 2008 Keep the setups coming. By the way this power supply was DOA and sent back at antec for replacement. So I have plenty of time to decide my final setup. Quote Link to comment
j5428 Posted March 2, 2008 Author Share Posted March 2, 2008 Got the new power supply from Antec. I currently have 10 Drives running on it. Quote Link to comment
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