[mythtv-users] Should I Upgrade Frontend from AMD 3200+ to AMD X2 3800+ (DualCore) ?

[Brian Wood]

On Saturday 14 February 2009 16:48:26 Krzysztof Adamski wrote:
> On Sat, 2009-02-14 at 17:42 -0500, Eric Holt wrote:
> > On Sat, Feb 14, 2009 at 5:00 PM, Brad Templeton
> >         Though right now I am buying all core 2 duo.   Most myth
> >         systems end
> >         up being up 24/7.    And being up 24/7 makes every watt of
> >         power count,
> >         and core 2 processors are lower power than the AMDs, unless
> >         AMD has changed
> >         a lot recently.
> >
> > Intel is still mostly producing processors that use 65w.  Check
> > NewEgg.  There are 2 processors on there that use 35w, but both of
> > those are single-core Celeron's.  All of the 45w processors are AMD.
> > Then Intel finally shows back up in the 65w range (as well as quite a
> > few more AMD processors).
> >
> > I have the 4850e, which is dual-core at 2.5ghz -- and 45w max power
> > usage.  AMD also now has the 5050e, which is 2.6ghz at 45w.
> >
> > I have a box running the 4850e, like I said, and a 80%+ efficient PSU
> > -- with AMD's cool-n-quiet enabled... that idles around 40w, and
> > barely hits 100w at full load.  Compared to my other box that was 65w
> > idle / 145w loaded -- thats a good bit of power savings.
> >
> > heh, I love having a Kill-a-Watt. :)
> > --Eric
>
> I just had a PSU die in my desktop/frontend computer. I was wondering
> what size of a PSU I need.
> The existing PSU is a 400 Watt Antec earthwatts using, when doing
> nothing the Kill-a-Watt shows a usage of 155W, and at full CPU
> utilization it would go up to 215W when transcoding something.
>
> So what size of PSU do I need for this computer, is there a rule of
> thumb for translating the Kill-a-watt usage in to the size of PSU that
> is needed?

The Kill-a-Watt tells you how much AC power you are inputting to the PSU from 
the wall, not how much DC power the PSU is supplying to the computer. The 
power draw of things like CPUs, HDDs etc. is specified as how much DC power 
they draw (after the PSU) .

The difference between the two depends on the efficiency factor of the PSU 
itself. So an HDD that says it draws 10 watts will draw perhaps 12 watts from 
the wall outlet, again depending on the efficiency of the PSU.

Note also that the KAW can read watts or volt-amps. Thw two are the same if 
the power factor is 1.0, and VAs will be higher than the watts if a reactive 
load is involved. You probably want to have the unit in watt mode.

Some power supplies run pretty inefficiently at loads that are well below the 
rated maximum, so you would probably not want a 1000 watt PSU if you are only 
using 200 watts.

Having said all that, a 350 or 400 watt PSU should be OK for what you want. 
Even a 500 watt unit would probably be fine.


-- 
beww
beww at beww.org