[vox] Good quiet hardware for Myth TV

[Bill Broadley]

On 04/25/2011 10:38 AM, Wes Hardaker wrote:
>>>>>> On Thu, 21 Apr 2011 11:39:03 -0700, Brian Lavender <brian at brie.com> said:
> 
> BL> I guess the biggest thing I am thinking about is noise and size,
> BL> similar to my existing Tivo box. It is very quiet.  Any
> BL> recommendations on cases and fans?
> 
> Sorry for the delay on this...
> 
> Everyone else's suggestions are good ones, but I'll mention some
> additional thoughts:
> 
> 1) High speed drives are faster

Heh, depends on how you define "faster".  I've not seen that bandwidth
correlates well with RPM, I'm assuming that the slower RPM drives end up
with more bits per inch.  Latency for seeks does though.

>    but slower speed ones are quieter (and
>    cooler).  And cooler is always quieter.

Indeed, assuming some ram for buffering it seems like few uses these
days requires the faster RPMs.

>    My low-power disks certainly
>    don't have the bandwidth of the high-speed disks, but they can record
>    multiple streams and play one at the same time without problems.

Not sure how smart the linux software is, the main trick is buffering
enough to seek less often.  There are AV optimized drives that tweak the
BIOS to do this in hardware at the cost of some latency for non-video
usage patterns.  They claim multiple HDTV streams.

Additionally in the next week or so I believe intel's coming out with a
new chipset called the z68 or something that has an optional or built in
20GB SSD designed specifically to provide a caching layer to speed up
random access I/O for a 1-2TB drive.  It will be interesting to see how
it performs.  I'm not sure if it requires a (likely windows only) driver
or if it's in ahrdwar.e

>    They're significantly cooler (by like 10 degrees C) than the non-LP ones.

Indeed, it's a pretty big win for many uses.  Less heat (so less noise
for cooling to the same temp) and less vibration (so less noise from the
drive and case).

> 2) You can find cases that are designed to be quiet, though every case
>    needs air holes so there is only so much that can be done.

That seems to overstate it a bit IMO.  There's numerous things to do
that can make a significant difference:
* Avoid FANs on chipset
* Shock mount the drives with rubber standoffs or straps/bungie cords.
  This makes the drive quieter, and transmits less vibration into the
  case.
* Get a case that uses larger fans.  The lower RPM causes less
  vibration and less turbulence and can move more air at the same
  noise level.  120mm fans for desktops work really well
* Get a powersupply and/or motherboard that can thermally control it's
  own fan and the case fans.
* Get a quality case that's either heavier gauge (less audible
  vibrations) or multiple layers.  Numerous cases are available
  that are multiple layer (usually plastic+metal) for better damping
  or having a sound absorbing inner layer.
* Of course enable speedstep or related to drop the CPU clock speed
  when idle.
* Get 5900rpm ish disks over 7200 rpm.

So if you take a cheap case, quad cpu, cheapest GPU, 2x2TB 7200 rpm
disks you typically end up with a pretty annoying system... at least for
a living room.  Often for minimally more money (i.e. $50-$100 per
system) you can get pretty close to silent, at least when not running
the CPU/GPU flat out.  On the low end the Antec Solo/Sonat and related
cases have suspended drives, 120mm fans (or two) and sound deading foam
inside the case.  For another $100-$200 you get fancier cases like the
P180-P183 that have multiple layers of metal and plastic.