Somewhat OT - can underpowered power supplies damage a system?

Suvayu Ali fatkasuvayu+linux at
Wed Aug 18 07:36:07 UTC 2010

On Tuesday 17 August 2010 10:27 PM, Thomas Cameron wrote:
> Say, hypothetically, I have 8 identical Intel DG45ID motherboard-based
> system with 8GB memory and a single drive with a cheap-o generic 300w
> power supply.

That is seriously overloaded I would say! Every motherboard should draw 
about 40~60W depending on the CPU and RAM you have on each of them! In 
the past I have damaged hard drives by stressing the PSU. (I had too 
many drives on one cable)

To keep stress on the PSU low, hardware review sites like Anandtech 
recommend running at the 60~80% mark of a PSU's power rating. That is 
the most efficient region for most PSU makes.

I would recommend you to look at the ampere and voltage ratings for all 
the components you have, and calculate the needed power for the components.

Power needed (W) = Ampere rating (A) x voltage rating (V)

Also it is very important to not overload any of the particular rails.
e.g. If one of the 12V rails for your PSU is rated at 120W then take 
care to put components such that the ampere ratings of all of them add 
up to 10A. (120W/12V = 10A)

Hope this helps.


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