January 15, 201115 yr 650 watt power supply. Intel Duo Core E6750 processor. Intel DQ35MP mainboard. 6 Western Digital Black 7200 RPM drives. My P3 killawatt indicates 100 watts at idle with all drives running. I guess this is what I'm paying for getting the higher RPM drives. I already had the power supply and didn't want to spend money on another one but just may...but I may eventually go to 10-12 drives.
January 15, 201115 yr Moving from a cheap power supply to a decent model could possibly net a 20W savings out of 100W. I saved 10W from my HTPC's 48W idle power usage with a power supply change. Peter
January 16, 201115 yr Author Specifically what power supply? I got curious so I checked out the power supply in this power hungry computer. And to my surprise it was only a 430watt power supply! How the heck am I sucking down 100 watts at idle? The power supply is a Thermaltake Purepower 430 NP. I have two 120mm fans and a CPU fan. Where is this computer pulling power from?
January 16, 201115 yr What's the efficiency of the power supply? If it's just typical and it looks like it is [ http://www.hardwaresecrets.com/article/Thermaltake-Purepower-430W-NP-Power-Supply-Review/332/7 ], then it's about 76% so it wastes 24% of the power it pulls in. The best power supplies are barely over 90%.
January 16, 201115 yr 43W for the drives (7W each - guess). 30W for chipset. 30W for CPU. 100W is not unreasonable with all drives spinning IMO.
January 17, 201115 yr Author What's the efficiency of the power supply? If it's just typical and it looks like it is [ http://www.hardwaresecrets.com/article/Thermaltake-Purepower-430W-NP-Power-Supply-Review/332/7 ], then it's about 76% so it wastes 24% of the power it pulls in. The best power supplies are barely over 90%. It looks like any grey color generic power supply with the Thermaltake label on it. Looks like I'm hunting for a nice power supply. Anyone recommend a top of the line power supply with good efficiency and can handle 10+ drives? Also, does picking up an 800watt power supply itself draw more power than a 650watt? Or do they just draw on what devices are being used?
January 17, 201115 yr Power supplies are most efficient when used in the upper range of their ability. If you have an 800w power supply that is supplying 200w of power and a 300w supply supplying 200w of power, assuming a perfect world, matched components, etc,etc. the 300w supply would be more efficient and draw less current from the grid. That said, a modern 800w might be more efficient at a 200w load than a 10 year old 300w When sizing you need to factor in worst case scenario (ie power-on spike, all drives spinning up at the same time, etc), component degradation over time, and overhead for growth. I'll defer to others who are more familiar with what's on the market in that size right now, my last build was focused on low power so I haven't looked for bigger supplies recently.
January 17, 201115 yr Not necessarily true. The 80+ Gold spec is to deliver maximum efficiency (90% efficiency or better), at 50% of rated load. See http://en.wikipedia.org/wiki/80_PLUS#Efficiency_level_certifications
January 17, 201115 yr Also, does picking up an 800watt power supply itself draw more power than a 650watt? Not necessarily. Each one will have an efficiency curve, or an efficiency for every possible load. It depends on which one is more efficient at the load you're placing on it. It's even possible one could be more efficient at one load but less efficient at a different load. I believe the 80plus ratings define efficiency requirements for different loads such as 25%, 50%, 75% or something like that. If you do some Google searching I bet you'd find good info on this. A good 800W supply would likely be overkill for a 10-16 drive server. I'd think a good 550W would be plenty. A good 650W should even work in a 20 drive system. What is the power usage with the disks spun-down? Peter
January 17, 201115 yr Also, does picking up an 800watt power supply itself draw more power than a 650watt? A good 800W supply would likely be overkill for a 10-16 drive server. I'd think a good 550W would be plenty. A good 650W should even work in a 20 drive system. Those statement are ONLY true if both are single rail power supplies. It is possible for a multi-rail 650 watt supply to have LESS 12 volt capacity than a 300 Watt supply on the one rail connected to the molex and SATA connectors.
January 17, 201115 yr If you're looking for a good PS for use with unRAID then you'd better be talking a model with a single 12V rail. Peter
January 17, 201115 yr Author What is the power usage with the disks spun-down? Peter With all the drives spun down it is 58.5 watts. So, 6 Western Digital Black drives use 40 watts. 6.6 watts each approx. Anyone have power watt usage with all drives spun down?
January 18, 201115 yr I'd say getting below 50W spun down is doing quite well and anything below that is just gravy but will likely require carefully picking lower power parts. I think my server is around 50W spun down. Peter
January 18, 201115 yr Author I will invest in a better more efficient power supply. All I ever heard about the Corsair's are good positive things.
January 18, 201115 yr If you plan on expanding with green drives then the Corsair 430W would be a good choice for you (for up to 10 drives, assuming your current 6 7200rpm drives and 4 new green drives). If you wish to continue expanding using 7200 rpm drives, then go for the Corsair 500W (for up to 10 drives), or the Corsair 550W (for up to about 13 drives), or the Corsair 650W (for up to about 17 drives).
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