Help me pick a CPU/Mobo

[Matthew Gillen]

David Kramer wrote:
> I started discussing this at the last meeting.  I'm looking to migrate
> most of the guts of my current server to my daughter's computer.
> 
> Right now I have a AMD Athlon XP 2400+ (with will be quite an upgrade
> from my daughter's current Celeron 466 or so).  It's almost always 95%
> idle or more.  But I just got MythTV up and running (next meeting,
> anyone?).  I have hardware encoding so recording isn't a problem, but
> when I need to transcode video with ffmpeg, it gets slammed.  And if I
> try to do that while it's recording, the box sometimes locks up cold and
> needs to be rebooted.
> 
> I'm not looking to go cutting edge.  In fact, I'm somewhat concerned
> about power consumption, which is why I'm trying to rule the world with
> one server.  But I do feel if I go dual core, ffmpeg can slam one core
> and everything else can get by on the other one.  Obviously I'll be
> going faster, too, and with more RAM for good measure.  I've never had a
> dual core machine before.

Athlons with a numerical component above 3300 (I think it's 3300) have
clock-throttling that linux can control, ie when it's idle it goes from
2.4GHz or [max-rated-clock-speed] to 1.0GHz.  The linux kernel actually lets
you control to some degree that functionality (ie when I switches to high
gear).  That keeps power usage down.  I have an AMD64 3300+ (not dual core),
and using one of those tiny shuttle cases, I'm using a 200W power supply
(which is the least powerful power supply of any computer I own).  Granted,
I don't have oodles of hard drives in there like you might want, but even
with a mid-range nVidia card in there too, I've never had problems with
power.  (and the shuttle case has heat pipes for the CPU, so there's not
even a CPU fan in the box; the only fan is in the power supply).

> I've also never had 64 bit before, but I'm considering that, too.  I've
> heard there are certain situations where it's actually slower, and I
> have an unfounded fear of not being able to find x86_64 packages.  I
> know it's stupid, but remember I'm 80% Software Engineer, 20% SysAdmin.

As far as x86_64 packages, it really depends on your distro.  Because I've
used it, I know Fedora supports everything on x86_64 that they support on
i386 (I use the AMD64 system to do my video editing with kino).

Unsupported packages (ie not in core or extras) are another story.  For a
while after the release of FC6, the proprietary nvidia and ati drivers for
x86_64 didn't work (they've worked for a long time now though).  And for a
long time if you wanted the proprietary flash plugin to work with firefox,
you had to jump through hoops to run the 32-bit version of firefox (again,
the vendor, macromedia in this case, finally got a x86_64 version out, so
this is no longer an issue).

So basically, check if the things you want are in core or extras.  If so,
you can be fairly confident that the x86_64 version will work.

w.r.t. it being slower in certain situations, I don't know.  I may be really
behind the times here, but I recently found out that Intel's hyperthreading
(two cores with one cache) could actually be significantly slower than the
same processor when it was turned off (because of cache-thrashing).
Explains why everyone's going full-dual-core nowadays...

In any event, if you have an article that explains the potential for slower
64-bit, I'd be interested to read it.

> So I'm looking for CPU/motherboard recommendations, and for someone to
> tell me I'm stupid for being afraid of 64 bit.

I hope I've convinced you about the 64-bit part ;-)

My main concern nowadays is noise since the baby took over my computer room
and now all my computers are in the living room.  So I like the shuttle
boxes with the no CPU fan + small power supply (here's the one I have:
http://global.shuttle.com/Product/Barebone/SK21G.asp , but my preferred
dealer doesn't carry Socket754-based Athlon64s anymore, or this particular
bare-bones kit, so YMMV).

Matt

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