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I am suspecting my PC to be running low on power, when I try to use an external hard drive (getting random I/O errors after I connect it, not all the time, only when both drives are busy). Is there any easy way to check if the power supply is supplying enough power for all components?

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How is the external drive connected and how is it powered? – Dennis Williamson Nov 10 '10 at 1:19
up vote 3 down vote accepted

USB can only provide 2.5W per port. I doubt 5W is going to change your PC from being stable to random errors - if it was running that close to the edge of the PSU you'd be getting more issues. Sounds more like a dodgy caddy/controller on the external drive.

Try either testing the drive internally (take it out the box, plug it in with IDE/SATA); or a different external disk.

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This site has a power supply calculator that should help you.

You fill in all the parts your computer has and it will calculate the recommended amount of Watts.

alt text

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Generically, try using a killawatt plug

Worth their weight in gold over time.

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