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#41
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Single-rail vs. multi-rail power supplies?
Yousuf Khan wrote: I currently have a desktop with a Zalman 600W PS, it was a pretty nice PS a few years ago when I got it, but now it looks like the system has been upgraded and grown again, and I'm starting to see signs that it's not producing enough power for the components anymore. mainly the optical drives sending controller error messages even when they are not being used, and I'm also noticing some occasional spin retry errors on a few of my internal HDD's. Bit-Tech.net says the 1GB Radeon 6870 uses from 128W - 247W. Power estimators aren't very good and usually give numbers that are way too high, and when XbitLabs.com took actual measurements, they got this (associated article goes into much more detail): http://www.xbitlabs.com/images/coole...attage/p40.png Or you could plug your system into a Kill-A-Watt and multiply the watt rating by about 80% to get the needed PSU wattage. BTW the maximum capacity of a PSU varies with temperature, and many years ago PC Power & Cooling said an Enermax rated for 550W @ 25C (room temperature) dropped to 366W @ 40C (not much hotter than some case interiors) and 244W @ 50C. If the drives are PATA instead of SATA, have you tried tightening the power connectors from the PSU? The connectors are metal tubes, and prying between them and their surrounding plastic can make them fit more snugly. I've had optical drives based on Philips designs (Acer/Benq/Aopen) suddenly act up and make head seeking noises, even when empty. I could never figure out what went wrong (reseated internal connectors, resoldered power chips, tapped all over the circuit boards, tried freeze spray), but if the drives were removed for a few months they'd work again, for up to a year. |
#42
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Single-rail vs. multi-rail power supplies?
larry moe 'n curly wrote
Yousuf Khan wrote I currently have a desktop with a Zalman 600W PS, it was a pretty nice PS a few years ago when I got it, but now it looks like the system has been upgraded and grown again, and I'm starting to see signs that it's not producing enough power for the components anymore. mainly the optical drives sending controller error messages even when they are not being used, and I'm also noticing some occasional spin retry errors on a few of my internal HDD's. Bit-Tech.net says the 1GB Radeon 6870 uses from 128W - 247W. The datasheet says nothing like that. Power estimators aren't very good and usually give numbers that are way too high, and when XbitLabs.com took actual measurements, they got this (associated article goes into much more detail): http://www.xbitlabs.com/images/coole...attage/p40.png And you dont have to measure with the 12V rail currents, they are in the datasheets. Or you could plug your system into a Kill-A-Watt and multiply the watt rating by about 80% to get the needed PSU wattage. Makes a hell of a lot more sense to calculate the 12V rail currents using the datasheets. And measure the system performance when you have a power supply that you are wondering if its adequate using a decent max min multimeter, BTW the maximum capacity of a PSU varies with temperature, Its normally determined by the currents that protection circuitry shut down at. and many years ago PC Power & Cooling said an Enermax rated for 550W @ 25C (room temperature) dropped to 366W @ 40C (not much hotter than some case interiors) and 244W @ 50C. Dont believe those numbers. If the drives are PATA instead of SATA, have you tried tightening the power connectors from the PSU? The connectors are metal tubes, and prying between them and their surrounding plastic can make them fit more snugly. Its better to release the contact from the shell and sqeeze the contact in a bit. Or just try a different connector and see if the errors are seen with that one too. In his case, because he has so many hard drives, it may even be the power Y adapters. I've had optical drives based on Philips designs (Acer/Benq/Aopen) suddenly act up and make head seeking noises, even when empty. I could never figure out what went wrong (reseated internal connectors, resoldered power chips, tapped all over the circuit boards, tried freeze spray), but if the drives were removed for a few months they'd work again, for up to a year. |
#43
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Single-rail vs. multi-rail power supplies?
On 23/03/2012 6:37 AM, Arno wrote:
You may also have a different problem, as 600W is really a lot. For example you may have filter capactiros on the mains side or the outputs siede that have lost a lot of their capacity. What symptoms are you observing? Well, I went through the power calculations elsewhere in the thread in a response to Rod. Basically, the only problem I'm having is with storage devices, both optical and hard drives. It's looking like all of the hard drives, combined with optical drives, and fans and LED's is pushing the current supply of one of the rails hard. The calculations showed that it's using between 178W to 217W. The nominal power rating of the rail is 192W. Yousuf Khan |
#44
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Single-rail vs. multi-rail power supplies?
In comp.sys.ibm.pc.hardware.storage Charlie wrote:
On 3/23/2012 6:05 PM, Yousuf Khan wrote: On 23/03/2012 11:56 AM, Charlie wrote: On 3/23/2012 12:39 AM, Yousuf Khan wrote: Were you overclocking? I'm not overclocking, at the moment. No, but I had lowered the voltage to reduce the heat. Its an I7 CPU. That didn't help much so I got a different heatsink which did help. When I looked at the Event logs I noticed that the optical drive errors started at about the time I lowered the voltage, so I raised the voltage and haven't had an optical drive error since (about 1 year). Well, then it seems like you put the CPU back to its recommended settings. My CPU is already at its recommended settings. Yousuf Khan I did not raise the voltage back to where it was. Just enough to stop the errors. I'm not saying that your errors are caused by the same thing as mine. Just giving you something else to try. In this case you will likely stikk have errors on occasion. You need to raise it to where the errors apprarently stop, and then a bit more. Of coruse if the errors are non-critical, you do what you did. But you should be aware that this can also cause other errors that may not be as visible. Arno -- Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F ---- Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans |
#45
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Single-rail vs. multi-rail power supplies?
Yousuf Khan wrote:
On 23/03/2012 6:37 AM, Arno wrote: You may also have a different problem, as 600W is really a lot. For example you may have filter capactiros on the mains side or the outputs siede that have lost a lot of their capacity. What symptoms are you observing? Well, I went through the power calculations elsewhere in the thread in a response to Rod. Basically, the only problem I'm having is with storage devices, both optical and hard drives. It's looking like all of the hard drives, combined with optical drives, and fans and LED's is pushing the current supply of one of the rails hard. The calculations showed that it's using between 178W to 217W. The nominal power rating of the rail is 192W. Ah, so you have a _theoretical_ result indicating possible errors. In that case you may want to redistribute your deicves a bit to the other rails, not replace the PSU. But note that typically, with a good quality PSU, 15% more load on one rail should not be an issue, as long as it is not permanent load and the device is overall not overloaded. You should also have had some overestimation in that calculation if you did it right. Arno -- Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F ---- Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans |
#46
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Single-rail vs. multi-rail power supplies?
In comp.sys.ibm.pc.hardware.storage Paul wrote:
Yousuf Khan wrote: On 23/03/2012 6:23 AM, Arno wrote: I suspect marketing. The onld ones were not really muti-rail either, more like "multi-rectifier". For proper multi-rail you have to have a regulator, power switches, rectifier and power-transformer for each rail. Probably, but the effect was the same, namely that each of the 4 +12V channels were limited in the amount of current they carried. It is also possible that recitifers have gotten better. Yeah, it had better be, or else I should be smelling smoke quite quickly. Yousuf Khan The only way a rectifier gets better, is by disappearing. No, definitely not. While syncronous rectifiers have their merits, they are mostly for switchers without transformers, as otherwise they drive cost up significantly. If you have very low voltages (CPU, RAM), they are the only sensible choice. In PSUs with transformers, typically you use normal power rectifiers, or shottky rectifiers. These have gotten slowly better and cheaper. Arno -- Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F ---- Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans |
#47
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Single-rail vs. multi-rail power supplies?
In comp.sys.ibm.pc.hardware.storage Yousuf Khan wrote:
On 23/03/2012 9:10 PM, Paul wrote: Yousuf Khan wrote: On 23/03/2012 6:23 AM, Arno wrote: It is also possible that recitifers have gotten better. Yeah, it had better be, or else I should be smelling smoke quite quickly. The only way a rectifier gets better, is by disappearing. In the picture here, the rectifier on the secondary is replaced by a MOSFET. ("Synchronous rectification") http://www.onsemi.com/pub_link/Collateral/AND8460-D.PDF Interesting. Standard concept, but too expensive with transformers. Arno -- Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F ---- Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans |
#48
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Single-rail vs. multi-rail power supplies?
Arno wrote: On 23/03/2012 9:10 PM, Paul wrote: The only way a rectifier gets better, is by disappearing. In the picture here, the rectifier on the secondary is replaced by a MOSFET. ("Synchronous rectification") http://www.onsemi.com/pub_link/Collateral/AND8460-D.PDF Standard concept, but too expensive with transformers. My only PSU with a MOSFET rectifier in it was so cheaply built that PC Power & Cooling featured it in an ad as an example of a bad PSU. |
#49
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Single-rail vs. multi-rail power supplies?
On 3/24/2012 9:11 AM, Arno wrote:
In comp.sys.ibm.pc.hardware.storage wrote: On 3/23/2012 6:05 PM, Yousuf Khan wrote: On 23/03/2012 11:56 AM, Charlie wrote: On 3/23/2012 12:39 AM, Yousuf Khan wrote: Were you overclocking? I'm not overclocking, at the moment. No, but I had lowered the voltage to reduce the heat. Its an I7 CPU. That didn't help much so I got a different heatsink which did help. When I looked at the Event logs I noticed that the optical drive errors started at about the time I lowered the voltage, so I raised the voltage and haven't had an optical drive error since (about 1 year). Well, then it seems like you put the CPU back to its recommended settings. My CPU is already at its recommended settings. Yousuf Khan I did not raise the voltage back to where it was. Just enough to stop the errors. I'm not saying that your errors are caused by the same thing as mine. Just giving you something else to try. In this case you will likely stikk have errors on occasion. Well, I consider a year without an optical drive error to be sufficient to believe the problem is fixed. :-) You need to raise it to where the errors apprarently stop, I did. and then a bit more. I can't see the point to that, but if I did start to get some errors of unknown origin I would definitely raise the voltage to see if it would help. Of coruse if the errors are non-critical, you do what you did. But you should be aware that this can also cause other errors that may not be as visible. I'm having no other problems. Charlie |
#50
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Single-rail vs. multi-rail power supplies?
Arno wrote:
In comp.sys.ibm.pc.hardware.storage Yousuf Khan wrote: On 23/03/2012 9:10 PM, Paul wrote: Yousuf Khan wrote: On 23/03/2012 6:23 AM, Arno wrote: It is also possible that recitifers have gotten better. Yeah, it had better be, or else I should be smelling smoke quite quickly. The only way a rectifier gets better, is by disappearing. In the picture here, the rectifier on the secondary is replaced by a MOSFET. ("Synchronous rectification") http://www.onsemi.com/pub_link/Collateral/AND8460-D.PDF Interesting. Standard concept, but too expensive with transformers. Arno Um, yeah, that's the transformer the ATX supply needs anyway. Compare the picture in AND8460-D.PDF to Pavouk, for some inspiration. Transformer T3 in the upper right of this picture, is the equivalent of the transformer present in the Onsemi appnote. The synchronous rectifier idea, would replace the diode pairs on the right of T3. http://www.pavouk.org/hw/en_atxps.html The advantage of the MOSFET, is no longer having to deal with the diode equation, and a rising voltage drop across the rectifier, as the current flow through it rises. If I run 20 amps through a rectifier diode, and the drop across it is 1 volt, that's 20W of heat. You then compare that to the channel resistance of the MOSFET (and the I**2*R loss there), and the amount of energy needed to drive the gate capacitance (it's a factor too). The Onsemi appnote shows 91% efficiency at mid-load (Figure 50 on PDF page 26). Paul |
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