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choosing PSU

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August 6, 2007 2:25:57 PM

ehmm well, i just bought
Western Digital Caviar SE WD1600JS 160GB 7200 RPM SATA 3.0Gb/s Hard Drive
MSI K9N4 SLI-F Socket AM2 NVIDIA nForce 500 SLI MCP ATX AMD Motherboard
SAPPHIRE 100186L Radeon X1950XT 256MB GDDR3 PCI Express x16 VIVO HDCP Video Card
AMD Athlon 64 X2 5600+ Windsor 2.8GHz Socket AM2 Processor Model ADA5600CZBOX
Sony NEC Optiarc 18X DVD±R DVD Burner Black E-IDE/ATAPI Model AW-Q170A-B2
G.SKILL 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model F2-6400CL5D-2GBNQ

and i would like to know what PSU should I buy now?? something maybe a bit higher than I actually need would be good, I dont wanna be pushing the psu or anything, thx

More about : choosing psu

August 6, 2007 4:19:16 PM

Corsair 520W its a little expensive, but well well worth it.
August 6, 2007 4:50:23 PM

Hi Gurak,

The power supply is one area where you definitely don't want to go "cheap"; it is the foundation of your system, and the performance and stability of all of the other components depend upon it. Choose a PSU from a reputable manufacturer, most of all. It doesn't appear that you have a very demanding system, but for future-proofing, I'd go with a supply having a single +12V rail for better power usage optimization. I would also avoid a modular supply, since the additional connectors used increase the resistance in the lines (a very bad thing), and connectors just represent another potential failure point.

Regards,

Altazi
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August 6, 2007 5:53:58 PM

altazi said:
I would also avoid a modular supply, since the additional connectors used increase the resistance in the lines (a very bad thing), and connectors just represent another potential failure point.


Do you disassemble your ATX connector and solder the leads to your mobo? Most don't - they use the connector. How many times have you heard of that connector failing? I'm talking about connection failure, not improperly plugging or accidentally unplugging it. How much is the resistance increase from a modular PS cable? (Don't go read it at the PCP&C website, speak from memory)

Modular power supplies are fine if they are quality units.
August 6, 2007 9:31:46 PM

great, thx, i know my system its not so demanding, but i still wanted to know about how much power i needed for my psu, so it sould be good enough with 500 - 550??
August 7, 2007 12:24:43 AM

clue69less said:
Do you disassemble your ATX connector and solder the leads to your mobo? Most don't - they use the connector. How many times have you heard of that connector failing? I'm talking about connection failure, not improperly plugging or accidentally unplugging it. How much is the resistance increase from a modular PS cable? (Don't go read it at the PCP&C website, speak from memory)

Modular power supplies are fine if they are quality units.


I am an electronic design engineer with almost 30 years of experience. How about you? I have seen connectors like these fail, in normal use. The current flowing through the connector times the resistance of the connector results in heat (P = I^2 R). This heat can cause the connector's resistance to rise, resulting in a thermal runaway condition that produces sufficient heat to destroy the connector. The connector melts, the PC board burns and turns black. It's not a pretty sight.

Connectors are to be avoided if reasonably possible, since they represent a potential failure point. Soldering the power wires to the motherboard is a bit over the top, since the PSU & motherboard have a reasonable need to be disconnected from one another for assembly and service purposes. However, IMO having two connectors in series with the high-current leads from the power supply is a questionable practice, since it is really only for cosmetic purposes. Just because a number of PSUs are built with modular connectors doesn't mean it's good engineering practice; rather, it just meets the needs of a particular segment of the market.

Furthermore, even though these supplies are of reasonable quality, I assure you that the components used are as low-cost as they can be - as it is for all consumer electronic devices. There isn't $0.01 of extra cost in any consumer product - the engineers are forced to pare it down to the absolute minumum. A PSU built with high-quality/high-reliability connectors would be too expensive for all but the richest enthusiasts to purchase. You'd miss the mass-market, and miss the economy of volume required to justify mass production of the product.

Regards,

Altazi
August 7, 2007 12:36:57 AM

Gurak said:
great, thx, i know my system its not so demanding, but i still wanted to know about how much power i needed for my psu, so it sould be good enough with 500 - 550??

Hi Gurak,

Try this power supply calculator, it should get you close. Go to the bottom of the page and select the "Lite" (free) version.

Regards,

Altazi
August 7, 2007 1:30:09 AM

Solariscs said:
Corsair 520W its a little expensive, but well well worth it.


Seconded. This is a high-quality PSU and it gives you enough room for upgrades.
!