[mythtv-users] Power supply for ATX

Jarod Wilson lists at wilsonet.com
Thu Jan 25 19:44:42 UTC 2007

Brian Wood wrote:
> On Jan 21, 2007, at 4:13 PM, Bill Williamson wrote:
>> On 1/21/07, Damian Surr <damian at gingermagic.com> wrote:
>>> only see ATX2 and high wattage power supply's. I think the one  
>>> that's in
>>> there is 300W and I don't really want to go any higher if I don't  
>>> have
>>> to as I don't want it to drink electricity.
>> Power supplies are rated on peak capacity, not power usage.  A 1KW
>> power supply will not draw any more power than a 300W power supply
>> hooked to the same computer, and may even draw LESS power as it will
>> likely be more effecient.
> True but incomplete.
> The rating of a PS is the total of the various voltages, so you  
> could, for example, overload the +12V output while still staying  
> within the total wattage rating of the supply.
> Add to that the fact that the manufacturers outright lie in a lot of  
> cases and the rating of a PS can become pretty meaningless.
> Then there are factors other than the voltage and current, like  
> ripple, regulation, power factor and others. The result is that two  
> supplies with identical "ratings" can be totally different animals.
> Especially for a supply for a Myth box, which tends to be on all the  
> time, the "power factor" and the overall efficiency should be taken  
> into consideration.
> It drives me crazy when I see an ad for a "600 watt supply - $19.95",  
> but such things are common.

Yep, 600W supplies in general are stupid. Who actually needs that much 
for a home system? Unless you have an SLI setup, quad dual-core chips, 
and 8 hard drives in your system, I fail to see how you'd need 600W. 
Hell, I have a box with an AGP card, 4 PCI cards, dual CPUs and 12 
drives in it (my master backend) that has only a 500W supply, and its 
been rock solid for the entire year and a half its existed. My frontend 
box (an Athlon 64 3500) has a mere 330W supply.

> The bottom line is that good power supplies are expensive, and you  
> get what you pay for. A good unit from PC Power and Cooling or  
> Thermaltake will cost you up front but pay for itself in the end.
> IMHO buy the best supply you can afford, you will never regret it.  
> Power supplies are the most overlooked parts of modern PCs, and the  
> cause of more problems than people suspect.

I've become quite partial to supplies that 1) carry 80plus certification 
(>80% efficiency) and 2) rate highly in silentpcreview.com's noise and 
quality testing.


More information about the mythtv-users mailing list