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#1
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Questions about power use
I want to build a very low power PC to act as my file and print server
for a home network. Sadly, I don't really understand "power" and was hoping to get some advice. I've been told that some devices use power/electricity even when you are not using them. Specifically devices that have a "black box" which plugs into the wall and a tiny DC connector. I assume the black box is a transformer/power converter (AC to DC) and that this uses energy even when the machine it supplies isn't on. With this in mind, I've been wondering whether a PC power supply similarly uses energy even when there is not much load. For instance, say you get a 350Watt power supply and have an old Duron700 with a CD drive and 1 hard drive… Is this system wasting power even though it doesn't need 350W? I understand that having an undersized power supply causes problems but does having an oversized power supply waste energy? Im going to try a VIA M1000 EPIA motherboard for my server. The Morex cases for this board include a 60W powersupply but they only have room for one harddrive and I need room for 2. My next case choice is an Antec Minuet but its power supply is 220W… Going from 60W to 220W is a big jump and I am assuming that my little system will not need so much power. I just want to know that using a larger power supply wont negate my intentions for the lower power CPU. |
#2
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"Purple" wrote in message om... I want to build a very low power PC to act as my file and print server for a home network. Sadly, I don't really understand "power" and was hoping to get some advice. I've been told that some devices use power/electricity even when you are not using them. Specifically devices that have a "black box" which plugs into the wall and a tiny DC connector. I assume the black box is a transformer/power converter (AC to DC) and that this uses energy even when the machine it supplies isn't on. With this in mind, I've been wondering whether a PC power supply similarly uses energy even when there is not much load. For instance, say you get a 350Watt power supply and have an old Duron700 with a CD drive and 1 hard drive. Is this system wasting power even though it doesn't need 350W? I understand that having an undersized power supply causes problems but does having an oversized power supply waste energy? Power ratings are maximums. If your PC uses 100W continuous, that is what it will use. It can use UP TO 350 watts for short periods of time without over-stressing your power supply, but if it only needs 100W, that's what it will use. -Dave |
#3
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I've been told that some devices use power/electricity even when you
are not using them. Specifically devices that have a "black box" which plugs into the wall and a tiny DC connector. I assume the black box is a transformer/power converter (AC to DC) and that this uses energy even when the machine it supplies isn't on. With this in mind, I've been wondering whether a PC power supply similarly uses energy even when there is not much load. For instance, say you get a 350Watt power supply and have an old Duron700 with a CD drive and 1 hard drive. Is this system wasting power even though it doesn't need 350W? I understand that having an undersized power supply causes problems but does having an oversized power supply waste energy? A supply that is much larger than needed may use slightly more power than one that is just able to supply the correct ammount of power. It will not really be noticed in the power bill in a years time. Sort of like a brick being added to a truck. It is there but small enough it is not noticed. It only uses the ammount of power the computer boards and hard drives need. A 200 watt supply and a 400 watt supply will draw almost the same ammount of power from the AC plug if they are powering the same computer boards, processor and drives. Use the larger supply and if you later need to add another hard drive it will be there. It will not watse any more noticable energy. |
#4
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Purple wrote:
I want to build a very low power PC to act as my file and print server for a home network. Sadly, I don't really understand "power" and was hoping to get some advice. =20 I've been told that some devices use power/electricity even when you are not using them. Specifically devices that have a "black box" which plugs into the wall and a tiny DC connector. I assume the black box is a transformer/power converter (AC to DC) and that this uses energy even when the machine it supplies isn't on. Yes, it's a little transformer/power converter and while 'technically' it= =20 uses some power when the connected device is off it's insignificant. With this in mind, I've been wondering whether a PC power supply similarly uses energy even when there is not much load. An ATX power supply ALWAYS has the standby voltages on. 'Off' simply turn= s=20 off the heavy power ones. For instance, say you get a 350Watt power supply and have an old Duron700 with a CD drive and 1 hard drive=85 Is this system wasting power even though it doesn't need 350W? Well, possibly, but that's a matter of where the power supply's maximum=20 efficiency point is and not all that easy to find out. It's not large,=20 compared to the PSU rating, but it's probably more than what the wall uni= t=20 would 'waste'. I understand that having an undersized power supply causes problems but does having an oversized power supply waste energy? Im going to try a VIA M1000 EPIA motherboard for my server. The Morex cases for this board include a 60W powersupply but they only have room for one harddrive and I need room for 2. My next case choice is an Antec Minuet but its power supply is 220W=85 You can get lower power units than that, you know. =20 Going from 60W to 220W is a big jump and I am assuming that my little system will not need so much power. I just want to know that using a larger power supply wont negate my intentions for the lower power CPU. |
#5
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Purple wrote:
I want to build a very low power PC to act as my file and print server for a home network. Sadly, I don't really understand "power" and was hoping to get some advice. I've been told that some devices use power/electricity even when you are not using them. Specifically devices that have a "black box" which plugs into the wall and a tiny DC connector. I assume the black box is a transformer/power converter (AC to DC) and that this uses energy even when the machine it supplies isn't on. With this in mind, I've been wondering whether a PC power supply similarly uses energy even when there is not much load. For instance, say you get a 350Watt power supply and have an old Duron700 with a CD drive and 1 hard drive… Is this system wasting power even though it doesn't need 350W? I understand that having an undersized power supply causes problems but does having an oversized power supply waste energy? Im going to try a VIA M1000 EPIA motherboard for my server. The Morex cases for this board include a 60W powersupply but they only have room for one harddrive and I need room for 2. My next case choice is an Antec Minuet but its power supply is 220W… Going from 60W to 220W is a big jump and I am assuming that my little system will not need so much power. I just want to know that using a larger power supply wont negate my intentions for the lower power CPU. Buy a Power Supply with 'Power Factor Correction' if you're concerned about your electrical bill. Interesting article: http://www.silentpcreview.com/article79-page2.html |
#6
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"Purple" wrote...
I want to build a very low power PC to act as my file and print server for a home network. Use a notebook if power is the primary concern, and you aren't worried about performance. With this in mind, I've been wondering whether a PC power supply similarly uses energy even when there is not much load. For instance, say you get a 350Watt power supply and have an old Duron700 with a CD drive and 1 hard drive. Is this system wasting power even though it doesn't need 350W? I understand that having an undersized power supply causes problems but does having an oversized power supply waste energy? A conventional ATX or EPS power supply will draw idle power even when the computer is in sleep mode. Some is for fans, some is because the motherboard draws some power in sleep mode. A newer MoBo with ACPI will draw less than 5 watts in sleep mode, and something over 30 watts (depending on processor and RAM) when operating, not including peripherals. The Intel D915G MoBo, for example, supports a max of 300 watts of DC power draw via the MoBo for all its cards and peripherals(ftp://download.intel.com/design/moth...v/C6860001.pdf). Im going to try a VIA M1000 EPIA motherboard for my server. The Morex cases for this board include a 60W powersupply but they only have room for one harddrive and I need room for 2. My next case choice is an Antec Minuet but its power supply is 220W. Going from 60W to 220W is a big jump and I am assuming that my little system will not need so much power. I just want to know that using a larger power supply wont negate my intentions for the lower power CPU. Check out the MoBo technical specs for actual power draw. Do the same for all add-in cards and peripherals. Figure out what the typical and max power draw will be. A modern power supply is most efficient when working at a "typical" load of approx 20-50% of its max rated load; the efficiency will be somewhat less at high and low power draws. Find a power supply with the highest efficiency rating you can, and sized accordingly. |
#7
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"Dave C." wrote...
Power ratings are maximums. If your PC uses 100W continuous, that is what it will use. It can use UP TO 350 watts for short periods of time without over-stressing your power supply, but if it only needs 100W, that's what it will use. -Dave Not quite... Maximum efficiency ratings are quoted for "typical" loads, approximately 20-50% of max rated load; efficiency drops off for lower and higher loads. So, if the expected normal draw for a system is 100W, and all power supplies have the same rated efficiency, choose a power supply between 200 and 500 watts for best efficiency. Granted, that's a wide range, but other considerations (e.g., $$ and projected max load) will help you decide which to buy. |
#8
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On Thu, 01 Jul 2004 22:06:43 -0600, )-()-( wrote:
Purple wrote: [snip? Going from 60W to 220W is a big jump and I am assuming that my little system will not need so much power. I just want to know that using a larger power supply wont negate my intentions for the lower power CPU. Buy a Power Supply with 'Power Factor Correction' if you're concerned about your electrical bill. Interesting article: http://www.silentpcreview.com/article79-page2.html Yes, very interesting indeed. Especially the (completely most stupidously one that I ever saw in an electrical power test report) statement which tries to lure you into believing that: "A PF of 0.5 means that to deliver 100W in AC to a PSU, your electric company actually uses 200W and this is most definitely shown in your electric bill.. 100W is lost or wasted." This is complete rubbish. This tester even hasn't a clue about the difference between reactive power (which does definitely NOT -- shouting intended -- appear on any small consumer's electricity bill) and active power (wich DOES appear on the bill). If the power consumed by the computer is for instance 100 Watts (yes: 'Watt', not Volt-Ampere) with a PF of 0.5, then the so called 'apparent power' is 200 VA (expressed in Volt-Ampere), but the so called 'real' or 'active' power is still 100 W. And this real, or active power is the only one appearin on the electricity bill of a simple consumer. Big companies are billed for the reactive power they consume, as this one increases the cable size needed to deliver the real power. And there are more lies published on this page: "PF is not ... , but it is very relevant to real electricity consumption and energy conservation." The same lie repeated. Me assumes this 'test lab' is the companies own marketing department. Flip |
#9
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You have a lot of questions.
First of all the AC/DC power converter. Works the same way as a power converter you might buy at radio shack. This plugs into a power board that further converts power into different power lines for 12v 5v 3.3v (+/-) Some of the voltages are used to power sensors that watch for power signals in low wattages. These things may include turning the power suppy on/off, power on for network, mouse, or keyboard or even Modem. Might also include some things like USB, Infra Red, etc. Here are some links that sell different power adapter kits: http://store.ituner.com/ituner/posoformi.html http://www.idotpc.com/TheStore/Perip...asp?Cate.id=14 I do not really like these things. I would prefer a small ATX power supply rated at 125-300 watts. 150 watts is probably about the right amount. I have had a problem with the 60 watt version not making enough power. There is a drawback to using the power boards with the AC to DC converter. The problem is the AC-DC converter uses power constantly. These types of transformers may cause a Ghost load even if your server dies they will not shut off. Some other options might be using a Linux operation system and running the server with no mouse or keyboard, or maybe not. Another option may be to use an externally powered or USB powered CDROM Drives. You only need a CD on a server to load the operating system. You could also use a low power Laptop ultra-thin cd drive, that uses less power. On a Dell the other day I saw a CDROM/Floppy combo. Mitsumi also makes a Flash/FDD floppy combo that works off of USB and FDD cables. Some motherboards may boot off of USB and some may not. You may see some other ideas at www.mini-itx.com In the long run it might be better to get a MATX motherboard. The Via C3 motherboards are also nice. If you are still looking maybe the AMD Sempron will come out soon. Even a nice 1.4 Gig Tulatin Core PIII Celeron would do well. I want to build a very low power PC to act as my file and print server for a home network. Sadly, I don't really understand "power" and was hoping to get some advice. I've been told that some devices use power/electricity even when you are not using them. Specifically devices that have a "black box" which plugs into the wall and a tiny DC connector. I assume the black box is a transformer/power converter (AC to DC) and that this uses energy even when the machine it supplies isn't on. With this in mind, I've been wondering whether a PC power supply similarly uses energy even when there is not much load. For instance, say you get a 350Watt power supply and have an old Duron700 with a CD drive and 1 hard drive… Is this system wasting power even though it doesn't need 350W? I understand that having an undersized power supply causes problems but does having an oversized power supply waste energy? Im going to try a VIA M1000 EPIA motherboard for my server. The Morex cases for this board include a 60W powersupply but they only have room for one harddrive and I need room for 2. My next case choice is an Antec Minuet but its power supply is 220W… Going from 60W to 220W is a big jump and I am assuming that my little system will not need so much power. I just want to know that using a larger power supply wont negate my intentions for the lower power CPU. |
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