December 13, 201213 yr Hey. I have been given an old rig thats about 4 years old and I'm just wondering how many Watts I should be aiming for when putting this UnRaid machine together. The power supply is a Silverstone 750W. Pretty sure its not single rail (I have only ever used PS's where all the cords come out at once. This once has multiple plugs on the back that that all attach to). I have read that you should really be going single rail but how much does it actually effect it? I would rather not have to spend NZ$150+ if I don't have to replacing it. The Processor is a Intel 3.0Ghz Core 2 Duo and the Motherboard is Giga-Byte GA-EP35-DS3. I have updated the firmware on the motherboard and disabled the HPA. I have also removed the BIOS battery (for about 30 mins or so, is that long enough?) and tested to see if its off by default, which it is (Everything else reset so I assume everything went back to default settings). The GFX card is an old PCI card I got from Trade me (NZ Auction website). Something from 1996 as the system wont boot without a gfx card attached (Boy, old PCI cards are not easy to find). Standard cooling... 1 rear case fan, CPU fan and a CM 4in3 drive bay as well so theres a fan there for the HDDs (just one at the moment. Current power draw with no hard drives is about 51.3 Watts. I'll be adding WD Greens so would assume thats going to go up around 5 Watts per hard drive (when reading/writing and 0.8 idol). Guess my question is... is 51 Watts a good base line for bare bones unRaid system. Especially if I haven't really spent anything on it or is it worth building from scratch with power saving in mind? (Im not sure what a new low powered system would draw). Cheers.
December 13, 201213 yr 51 watts is a reasonable figure. It is possible with the right hardware to go lower, down to 35, or even under 30. However, it depends on the CPU and disk controller hardware, as well as the drives and the spin-down settings, and the efficiency of the power supply. There can be a low of diminishing returns - it's best not to over think this - you can spend a lot to save 15 watts, when the cost of the energy (and the energy required to manufacture new parts) can greatly exceed any potential savings. As for the power supply - single rail is good since it allows the maximum power available to go to the disk drives when they all spin up at the same time. However, you would need to look up the specs for the unit that you have. The connector arrangement (yours sounds like a "modular" supply) will not generally tell you anything about who the 12 volt rails are generated.
December 13, 201213 yr Author This is the Power Supply. http://www.silverstonetek.com/product_legacy.php?area=en&model=da750 Turns out it is a single rail with modular cables. I guess once I get past 6 hard drives I can just use a Molex to Sata cable to power the other hard drives? How will splitters effect it (1 molex to 2 sata?).
December 13, 201213 yr 1 Molex to 2 SATA is normally OK. You can get bad splitters (like any cheap cable), but I have three of the things in my server and things are generally stable.
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