[mythtv-users] The elusive silent myth BE/FE box [in search of]
raymond at wagnerrp.com
Sat Aug 20 23:37:12 UTC 2011
On 8/20/2011 18:30, Epinephrine Junky wrote:
>> (iii) Your pico-PSU may sound a good idea but remember you'll get losses
> in the power brick as well, say 7 to 10W.
> True but the beauty of that is that the heat is dumped outside the box so
> it doesn't contribute to (over)heating the CPU.
Not exactly. Say you've got a system that tops out at 100W. That power
supply is going to add another 15-20W into the mix. However that power
supply is dumping straight out the back of the system, and drawing air
from inside the system to do so. Not only is it not making the system
hotter, it's actually helping to cool it.
Things like the PicoPSU are fantastic if you have an existing 12V power
distribution system, or want to hook it up in-line with a battery
backup. If you are just going to plug it into a power adapter, the only
thing it gets you is a smaller lighter case, in exchange for a big brick
>> > (iv) I'd say you would be mad to try and run this without anything but a
>> case fan.
> Maybe but I've been called worse. I was thinking of these fanless
> If I had the $ to spend they seem to have the right idea... just way too
They don't quite have it figured out. The lack of fans on that much
power is severely restricting. First, you have to rely on convective
currents for all your cooling, which means you need to be out in the
open. If you have anything within half a foot on either side, there is
not going to be enough airflow over those fins to cool it. Similarly,
if anything is placed half a foot or so above it, you're going to block
those currents, and the system will overheat. This is something
designed to sit on top of a table next to your TV and look pretty.
Putting it in an AV rack is out of the question.
Second, the only things they cool are the CPU and graphics. There is no
provision for cooling the memory, power supply, chipset, or MOSFETs.
They're using a fanless power supply. Fanless power supplies expect
that the case will supply sufficient airflow through it to make up for
its own lack. Antec designed their dual chamber cases specifically to
allow for such power supplies, to ensure they had enough airflow through
them for stable operation. If you don't cool those and run the system
hard, they're going to overheat, their rated output will drop, and their
voltages will go out of spec, leading to system instability.
Memory needs cooling. Un-cooled memory will heat up, and lead to
reduced stability. They did go with one stick of pretty low end stuff,
which should help in this regard. Modern motherboards all have big
heatsinks around their chipsets and MOSFETs, and these are arrayed
around the processor, with the intent of scavenging airflow from the CPU
fan. With no fans, they don't get this, meaning they heat up, and
again, reduced system stability. These things seem nice in concept, but
at least in my opinion, they've overlooked too many issues for me to be
comfortable using one.
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