[mythtv-users] external power supply rant (Was: Zotac ION M/B..)

[Raymond Wagner]

Simon Hobson wrote:
> From the efficiency point of view, it means that ALL power consumption 
> goes through two conversions instead of one. OK, there is still the 
> step down for the CPU supply, but 5V and 12V loads will come directly 
> from the PSU and have just one conversion.
Who cares?  DC-DC conversion is very efficient.  Beyond that, the vast 
majority of these machines are going to be dedicated frontend machines, 
meaning they will boot off the network, off a memory card, or at least 
have a hard drive that is kept spun down nearly all the time.  The only 
power draw of concern will be the northbridge, CPU, RAM, and any 
additional chips on the board, all of which will have to go through 
additional voltage conversion/regulation.

The real problem of concern is that 'wall-warts' are cheaply built, 
typically linear, and always low efficiency.  They will be dumping 
easily twice the waste heat of a traditional computer power supply.