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

[Allen Edwards]

On Sat, Feb 14, 2009 at 4:05 PM, Krzysztof Adamski <k at adamski.org> wrote:

> On Sat, 2009-02-14 at 16:56 -0700, Brian Wood wrote:
> > 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.
>
> So to put it in a simple terms :-)
> If the max draw at the KAW shows is 220W and we us a 80+ PSU that has a
> 99% power correcting, then (220W + 10% safety) for 242W at 80%
> efficiency gives us a 290W, so a 300W 80+ PSU should be more then
> enough, right?
>
> K
>

There is a power supply calculator on the ASUS site that will answer your
question directly.
http://support.asus.com/PowerSupplyCalculator/PSCalculator.aspx?SLanguage=en-us

Cheers,

Allen
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