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Power supply adivice needed
Ray wrote:
I have a ASUS P5B-E mo, a GeForce 9500 GT video, 4 sata hard drives (with sata and Molex connectors) and 5 usb peripherals and need a power supply to run it. The GF9500GT video card wants 18 amps so I am thinking of getting one of these supplies: 1. OXZ OCZ500MXSP http://www.newegg.com/Product/Produc...6&Tpk=OCZ500MX SP 2. CoolerMaster RS-460-PSAR-J3 http://www.newegg.com/Product/Produc...6&cm_re=RS-460 -PSAR-J3-_-17-171-046-_-Product 3. CoolerMaster RS-500 PCAR-A3-US http://www.newegg.com/Product/Produc...1&Tpk=rs-500pc ar-a3-us I like the idea of the modular wiring with the OCZ supply but was wondering if the relatively low -5v (.3a) is a possible problem. This one is more efficient too and has lots of connections but, of course, costs more. My question is: Which one is the best fit for my computer? Or if you think there are better choices with about the same cost, what would you suggest? Thanks, Ray Opps, I made a mistake and wrote "-5v" when I meant -12v. It seems most supplies have 0.8 amp for the -12v line. Should have typed "1. OCZ" (not OXZ) also. I guess I'm dizzy from looking at so many specs and comments. I didn't remember the ones for the CoolerMaster supplies. I did see the comments for the OCZ but they looked better than a lot of others I've seen. I had a EnerMax 420W supply but it broke down after a few years and that is why I need a new supply. It also seemed to be somewhat under powered for my system too. I have an Intel Core 2 Duo E6400 CPU. The GeForce 9500GT (PCI-E but no separate power connector) spec sheet says a minimum of 350 W power supply with a min recommended +12v current rating of 18 amps. so I assume that means for that power rail that supports the mob. Isn't this right? I have been trying to find supplies with +12v rails supporting 18 amps and there don't seem to be many under $100. Any suggestions? Ray |
#2
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Power supply adivice needed
Ray wrote:
Ray wrote: I have a ASUS P5B-E mo, a GeForce 9500 GT video, 4 sata hard drives (with sata and Molex connectors) and 5 usb peripherals and need a power supply to run it. The GF9500GT video card wants 18 amps so I am thinking of getting one of these supplies: 1. OXZ OCZ500MXSP http://www.newegg.com/Product/Produc...6&Tpk=OCZ500MX SP 2. CoolerMaster RS-460-PSAR-J3 http://www.newegg.com/Product/Produc...6&cm_re=RS-460 -PSAR-J3-_-17-171-046-_-Product 3. CoolerMaster RS-500 PCAR-A3-US http://www.newegg.com/Product/Produc...1&Tpk=rs-500pc ar-a3-us I like the idea of the modular wiring with the OCZ supply but was wondering if the relatively low -5v (.3a) is a possible problem. This one is more efficient too and has lots of connections but, of course, costs more. My question is: Which one is the best fit for my computer? Or if you think there are better choices with about the same cost, what would you suggest? Thanks, Ray Opps, I made a mistake and wrote "-5v" when I meant -12v. It seems most supplies have 0.8 amp for the -12v line. Should have typed "1. OCZ" (not OXZ) also. I guess I'm dizzy from looking at so many specs and comments. I didn't remember the ones for the CoolerMaster supplies. I did see the comments for the OCZ but they looked better than a lot of others I've seen. I had a EnerMax 420W supply but it broke down after a few years and that is why I need a new supply. It also seemed to be somewhat under powered for my system too. I have an Intel Core 2 Duo E6400 CPU. The GeForce 9500GT (PCI-E but no separate power connector) spec sheet says a minimum of 350 W power supply with a min recommended +12v current rating of 18 amps. so I assume that means for that power rail that supports the mob. Isn't this right? I have been trying to find supplies with +12v rails supporting 18 amps and there don't seem to be many under $100. Any suggestions? Ray The value the video card advertising recommends, is based on some assumptions about the contents of your computer case. The assumptions may not be valid. Let's try some numbers. E6400 = 65W. 65W/12V * 1/0.90 = 12V @ 6 amps from 12V2 rail, (90% Vcore efficiency) http://ark.intel.com/Product.aspx?id...T9,SL9TY,SLA97 The rest of the loads will be from 12V1. (4) hard drives. While idle in desktop, 0.6 amps each. Total 12V @ 2.4A from 12V1. When the hard drives spin up, the current is 2.5A for each drive, or about 10A total. When there are enough drives, a separate calculation should be carried out. Four drives happens to be the limit, before a person should calculate startup power requirements. Many supplies can withstand an overage on current during startup, but if you have enough hard drives, the startup current can crush the supply, and OC shuts off the power before the computer can POST. Overcurrent detection on an ATX supply, is likely disabled for the first 35 milliseconds, but is enabled from then on. (1) CDROM. About 12V @ 1.5A boiler plate rating. I've measured 12V @ 1.0A while media was spinning at top speed. This is from 12V1. If you have no media in the tray, the current is zero. (1) 9500 GT. 12V @ 4A approx from 12V1. (x) Cooling fans. Guess 12V @ 0.5A as an estimated total. Read the current rating on each fan hub, for an exact number. From 12V1 rail. Total so far, at idle in the desktop 12V2 @ 6 amps CPU 12V1 @ 2.4+1.5+4.0+0.5 = 12V1 @ 8.4A HDD/ODD/video/fans That's a total of 14.4 amps from both rails. If we look at startup current, for the first ten seconds, the processor is not running full power. The number is less. The BIOS might be using one core. So this would be during the first 10 seconds. The video card is also not at max power, because it isn't in 3D mode. We'll cut the power on that in half as well (if Xbitlabs had numbers, I could provide actual values for this). 12V2 @ 3 amps CPU 12V1 @ 10.0+1.5+2.0+0.5 = 12V1 @ 14A HDD/ODD/video/fans In terms of total system power (watts), I need to include some 5V current for the HDD and ODD. 5V @ 1A per hard drive. 5V @ 1.5A for optical. Also, I include 50W for motherboard chipset and RAM DIMMs. Some DIMMs now, are 2W each. Include 10W for +5VSB to power USB bus devices. I use the "long term power" numbers for this calculation, with CPU at full power, video card at full power. 12V * (6+8.4A) + 4*5*1 + 1*5*1.5 + 50 + 10 = 172.8 + 20 + 7.5 + 50 + 10 = 260.3W so that would be an upper limit. I have an Intel processor here, that is rated at 65W, that won't draw more than 36W under actual usage, so the number on a real system is likely lower than the 260W I just calculated. I just bought this yesterday, but the shipper hasn't delivered it yet. This is to give you an example of how cheaply you can meet the numbers. http://images17.newegg.com/is/image/newegg/17-103-013-S03?$S640W$ http://www.newegg.com/Product/Produc...82E16817103013 3.3V @ 30A 5V @ 28A 12V1 @ 18A (enough to not only spin up the drives, but run continuously at that level) 12V2 @ 18A (plenty for just the processor) +5VSB @ 2A (not a lot, but sufficient. May require unplugging some USB if there is trouble) -12V @ 0.5A (don't care...) (3.3V & 5V = 150W max) compare to 50W + 4*5*1 + 1*5*1.5 = 77.5W (12V1 & 12V2 = 348W max) compare to our 172.8W figure, about half load (DC output 400W) compare to 260W calculated The supply meets our needs. And that power supply is $45. I'm putting that power supply in my oldest system, so I can move a better supply up into another computer. The supply is likely not going to meet 80% efficiency, so I wouldn't necessarily want to be running it 24 hours per day. The better supply, has a higher efficiency, so I can afford to leave it running if necessary. Another advantage of that SPI supply, is no Active PFC, so no nasty reactions to my UPS switching to battery operation. I suspect my UPS makes the red waveform shown in this picture, when the UPS is running from battery, and that little SPI supply has no power factor correction, to get tied in knots by a square wave. The core of an ATX supply, doesn't care that the AC waveform is a square wave, but the recently introduced Active PFC on power supplies (which sits in front of the regular ATX power supply design), does care about waveshape, as the Active PFC reacts to waveshape in an attempt to correct it. So far, I have *no* active PFC supplies in the house. It's not that I don't like Active PFC, merely that it isn't that compatible with my ancient UPS. http://i285.photobucket.com/albums/l...ppedPure-1.jpg You can certainly cure that problem, with a purer sine wave UPS, but I really don't have the money to waste on that. Even if my UPS died tomorrow (and it may), based on economics, all I could afford is another square wave one. So I can't afford to buy any Active PFC ATX supplies, and find out the combination is not happy. Sometimes, you can spot those problems, by reading reviews on Newegg, for an Active PFC supply. This is a short blog on PFC, which doesn't show what happens. But it does warn about mixing them. http://www.dougv.com/blog/2010/03/01...t-low-end-ups/ "This I learned the hard way, as my Antec EarthWatts EA 500 PSU, which I adore, will go dead the second the battery on my APC Back-UPS BX1300LCD kicks in." And that behavior, kinda negates why we have UPSes on computers :-) My UPS is there, primarily to cover the one second outages we get here, rather than power the computer for a couple hours. HTH, Paul |
#3
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Power supply adivice needed
In article , "Ray" wrote:
Ray wrote: I have a ASUS P5B-E mo, a GeForce 9500 GT video, 4 sata hard drives (with sata and Molex connectors) and 5 usb peripherals and need a power supply to run it. The GF9500GT video card wants 18 amps so I am thinking of getting one of these supplies: 1. OXZ OCZ500MXSP http://www.newegg.com/Product/Produc...6&Tpk=OCZ500MX SP 2. CoolerMaster RS-460-PSAR-J3 http://www.newegg.com/Product/Produc...6&cm_re=RS-460 -PSAR-J3-_-17-171-046-_-Product 3. CoolerMaster RS-500 PCAR-A3-US http://www.newegg.com/Product/Produc...1&Tpk=rs-500pc ar-a3-us I like the idea of the modular wiring with the OCZ supply but was wondering if the relatively low -5v (.3a) is a possible problem. This one is more efficient too and has lots of connections but, of course, costs more. My question is: Which one is the best fit for my computer? Or if you think there are better choices with about the same cost, what would you suggest? Thanks, Ray Opps, I made a mistake and wrote "-5v" when I meant -12v. It seems most supplies have 0.8 amp for the -12v line. Should have typed "1. OCZ" (not OXZ) also. I guess I'm dizzy from looking at so many specs and comments. I didn't remember the ones for the CoolerMaster supplies. I did see the comments for the OCZ but they looked better than a lot of others I've seen. I had a EnerMax 420W supply but it broke down after a few years and that is why I need a new supply. It also seemed to be somewhat under powered for my system too. I have an Intel Core 2 Duo E6400 CPU. The GeForce 9500GT (PCI-E but no separate power connector) spec sheet says a minimum of 350 W power supply with a min recommended +12v current rating of 18 amps. so I assume that means for that power rail that supports the mob. Isn't this right? I have been trying to find supplies with +12v rails supporting 18 amps and there don't seem to be many under $100. Any suggestions? Ray For my own builds i never go less than a 600Watt supply and i am very hooked on the Modular type supplies. I love the fact that you only use what cables you need. If say my system has only SATA drives and no old EIDE drives, why have 6-8 old Molex plugs on a pair of 2 foot cords all messing up the inside of my case?????? |
#4
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Power supply adivice needed
"GMAN" wrote in message
... In article , "Ray" wrote: Ray wrote: I have a ASUS P5B-E mo, a GeForce 9500 GT video, 4 sata hard drives (with sata and Molex connectors) and 5 usb peripherals and need a power supply to run it. The GF9500GT video card wants 18 amps so I am thinking of getting one of these supplies: 1. OXZ OCZ500MXSP (skip) Opps, I made a mistake and wrote "-5v" when I meant -12v. It seems most supplies have 0.8 amp for the -12v line. Should have typed "1. OCZ" (not OXZ) also. I guess I'm dizzy from looking at so many specs and comments. I didn't remember the ones for the CoolerMaster supplies. I did see the comments for the OCZ but they looked better than a lot of others I've seen. I had a EnerMax 420W supply but it broke down after a few years and that is why I need a new supply. It also seemed to be somewhat under powered for my system too. I have an Intel Core 2 Duo E6400 CPU. The GeForce 9500GT (PCI-E but no separate power connector) spec sheet says a minimum of 350 W power supply with a min recommended +12v current rating of 18 amps. so I assume that means for that power rail that supports the mob. Isn't this right? I have been trying to find supplies with +12v rails supporting 18 amps and there don't seem to be many under $100. Any suggestions? Ray For my own builds i never go less than a 600Watt supply and i am very hooked on the Modular type supplies. I love the fact that you only use what cables you need. If say my system has only SATA drives and no old EIDE drives, why have 6-8 old Molex plugs on a pair of 2 foot cords all messing up the inside of my case?????? I like the modular concept too but in actual use don't know if it would save me much cabling anyway - I need both SATA and Molex anyway. It would eliminate the PCI-E cable since I don't do SLI. Maybe nice when I have to change components. From what I see and have read, the wattage ratings don't tell much - it's the current ratings for the needed voltage rails that counts. As I mentioned, I have a problem finding the 18 amp +12v line for the graphics card. Also worried about enough current for the HD/DVD/CD drives and USB. |
#5
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Power supply adivice needed
"Paul" wrote in message
... Ray wrote: Ray wrote: I have a ASUS P5B-E mo, a GeForce 9500 GT video, 4 sata hard drives (with sata and Molex connectors) and 5 usb peripherals and need a power supply to run it. The GF9500GT video card wants 18 amps so I am thinking of getting one of these supplies: 1. OXZ OCZ500MXSP (skip) there are better choices with about the same cost, what would you suggest? Thanks, Ray Opps, I made a mistake and wrote "-5v" when I meant -12v. It seems most supplies have 0.8 amp for the -12v line. Should have typed "1. OCZ" (not OXZ) also. I guess I'm dizzy from looking at so many specs and comments. I didn't remember the ones for the CoolerMaster supplies. I did see the comments for the OCZ but they looked better than a lot of others I've seen. I had a EnerMax 420W supply but it broke down after a few years and that is why I need a new supply. It also seemed to be somewhat under powered for my system too. I have an Intel Core 2 Duo E6400 CPU. The GeForce 9500GT (PCI-E but no separate power connector) spec sheet says a minimum of 350 W power supply with a min recommended +12v current rating of 18 amps. so I assume that means for that power rail that supports the mob. Isn't this right? I have been trying to find supplies with +12v rails supporting 18 amps and there don't seem to be many under $100. Any suggestions? Ray The value the video card advertising recommends, is based on some assumptions about the contents of your computer case. The assumptions may not be valid. Let's try some numbers. E6400 = 65W. 65W/12V * 1/0.90 = 12V @ 6 amps from 12V2 rail, (90% Vcore efficiency) http://ark.intel.com/Product.aspx?id...ec-codes=SL9S9, SL9T9,SL9TY,SLA97 The rest of the loads will be from 12V1. (4) hard drives. While idle in desktop, 0.6 amps each. Total 12V @ 2.4A from 12V1. When the hard drives spin up, the current is 2.5A for each drive, or about 10A total. When there are enough drives, a separate calculation should be carried out. Four drives happens to be the limit, before a person should calculate startup power requirements. Many supplies can withstand an overage on current during startup, but if you have enough hard drives, the startup current can crush the supply, and OC shuts off the power before the computer can POST. Overcurrent detection on an ATX supply, is likely disabled for the first 35 milliseconds, but is enabled from then on. (1) CDROM. About 12V @ 1.5A boiler plate rating. I've measured 12V @ 1.0A while media was spinning at top speed. This is from 12V1. If you have no media in the tray, the current is zero. (1) 9500 GT. 12V @ 4A approx from 12V1. (x) Cooling fans. Guess 12V @ 0.5A as an estimated total. Read the current rating on each fan hub, for an exact number. From 12V1 rail. Total so far, at idle in the desktop 12V2 @ 6 amps CPU 12V1 @ 2.4+1.5+4.0+0.5 = 12V1 @ 8.4A HDD/ODD/video/fans That's a total of 14.4 amps from both rails. If we look at startup current, for the first ten seconds, the processor is not running full power. The number is less. The BIOS might be using one core. So this would be during the first 10 seconds. The video card is also not at max power, because it isn't in 3D mode. We'll cut the power on that in half as well (if Xbitlabs had numbers, I could provide actual values for this). 12V2 @ 3 amps CPU 12V1 @ 10.0+1.5+2.0+0.5 = 12V1 @ 14A HDD/ODD/video/fans In terms of total system power (watts), I need to include some 5V current for the HDD and ODD. 5V @ 1A per hard drive. 5V @ 1.5A for optical. Also, I include 50W for motherboard chipset and RAM DIMMs. Some DIMMs now, are 2W each. Include 10W for +5VSB to power USB bus devices. I use the "long term power" numbers for this calculation, with CPU at full power, video card at full power. 12V * (6+8.4A) + 4*5*1 + 1*5*1.5 + 50 + 10 = 172.8 + 20 + 7.5 + 50 + 10 = 260.3W so that would be an upper limit. I have an Intel processor here, that is rated at 65W, that won't draw more than 36W under actual usage, so the number on a real system is likely lower than the 260W I just calculated. Looks like my response didn't get to the newsgroup so I'll repeat it here. Sorry if it shows up twice. Thanks for the detailed analysis. I forgot to mention an additional tray mounted HD and I have a DVD as well as a CD drive but those should fit in without much additional current demands. I like the modular designs and would like to find a supply that has sufficient ASATA and Molex connetors to handle my loads without a lot of extentions needed. I'll take a look at the supply you mention below. Except for cables, it seems to handle enough currents. Thanks again. I just bought this yesterday, but the shipper hasn't delivered it yet. This is to give you an example of how cheaply you can meet the numbers. http://images17.newegg.com/is/image/newegg/17-103-013-S03?$S640W$ http://www.newegg.com/Product/Produc...82E16817103013 3.3V @ 30A 5V @ 28A 12V1 @ 18A (enough to not only spin up the drives, but run continuously at that level) 12V2 @ 18A (plenty for just the processor) +5VSB @ 2A (not a lot, but sufficient. May require unplugging some USB if there is trouble) -12V @ 0.5A (don't care...) (3.3V & 5V = 150W max) compare to 50W + 4*5*1 + 1*5*1.5 = 77.5W (12V1 & 12V2 = 348W max) compare to our 172.8W figure, about half load (DC output 400W) compare to 260W calculated The supply meets our needs. And that power supply is $45. I'm putting that power supply in my oldest system, so I can move a better supply up into another computer. The supply is likely not going to meet 80% efficiency, so I wouldn't necessarily want to be running it 24 hours per day. The better supply, has a higher efficiency, so I can afford to leave it running if necessary. Another advantage of that SPI supply, is no Active PFC, so no nasty reactions to my UPS switching to battery operation. I suspect my UPS makes the red waveform shown in this picture, when the UPS is running from battery, and that little SPI supply has no power factor correction, to get tied in knots by a square wave. The core of an ATX supply, doesn't care that the AC waveform is a square wave, but the recently introduced Active PFC on power supplies (which sits in front of the regular ATX power supply design), does care about waveshape, as the Active PFC reacts to waveshape in an attempt to correct it. So far, I have *no* active PFC supplies in the house. It's not that I don't like Active PFC, merely that it isn't that compatible with my ancient UPS. http://i285.photobucket.com/albums/l...ppedPure-1.jpg You can certainly cure that problem, with a purer sine wave UPS, but I really don't have the money to waste on that. Even if my UPS died tomorrow (and it may), based on economics, all I could afford is another square wave one. So I can't afford to buy any Active PFC ATX supplies, and find out the combination is not happy. Sometimes, you can spot those problems, by reading reviews on Newegg, for an Active PFC supply. This is a short blog on PFC, which doesn't show what happens. But it does warn about mixing them. http://www.dougv.com/blog/2010/03/01...re-not-compata ble-with-most-low-end-ups/ "This I learned the hard way, as my Antec EarthWatts EA 500 PSU, which I adore, will go dead the second the battery on my APC Back-UPS BX1300LCD kicks in." And that behavior, kinda negates why we have UPSes on computers :-) My UPS is there, primarily to cover the one second outages we get here, rather than power the computer for a couple hours. HTH, Paul |
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