how to determine PSU wattage

[Oleg Goldshmidt]

shimi <linux-il at shimi.net> writes:

> Not really. What you really should be looking at is the maximum
> amperage on the specific voltage rails you're going to use... the
> total maximum of all rails is meaningless... if you don't have enough
> amperes on the specific voltage you actually consume from... and if
> the PSU doesn't have protection, you might even fry it...

[Replying to both responses to my previous post - thanks, guys!]

I know all of that, but I was not at all concerned about the power (or
current - they are effectively equivalent if your 12V is there) drawn by
the new card. The box is not overloaded by HW, and the card is not
particularly demanding (well, I could get a higher end model, but I
didn't even consider that, primarily due to power considerations).

All I wanted to do was to get a rough idea of the total power
requirements of my pure vanilla components (MoBo + CPU + RAM + HD + fans
+ DVD/RW + USB + the new card) and make sure that my PSU - also pure
vanilla and acquired without any special thoughts - would not be
overwhelmed. This is what is done by those power calculators, and I do
think they have a safety margin built it - if your configuration draws
398W they won't show 400W as sufficient.

I was not building a high end "gamer's" box with super-overclocked
graphics, a monster NIC, 5 HD's, 8 fans, and 128GB of RAM, which is
where finer considerations like those you mentioned come into play.

FWIW, the card is in and is working fine so far [that's half a day
uptime already :-)]. It's max power is 65W, not 165W. ;-) I could (and
did, in the end) power the box down and look inside, but I didn't want
to, for some good but uninteresting reasons, and because I was loath to
do it before exhausting "software" options. And, of course, I was
curious - always a good excuse for me.

Thanks again, and sorry for making you think I had less trivial needs,

-- 
Oleg Goldshmidt | pub at goldshmidt.org