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CPU Fan Speed Control
Like the other Shuttle XPC systems, the ST62K BIOS gives users
control over the ICE exhaust fan. Since the ICE fan is the only active
cooling component, controlling the fan speed will have a greater impact on
overall noise than with other Shuttle systems that also feature multiple fans.
BIOS Fan Control Setting screen. Set in
"Smart Fan" mode with a 60°C threshold. Note the Vcore of 1.32V.
More on this later.
The BIOS offers five different fan settings to balance noise levels
with processor temperatures. I used the "Smart Fan" mode
with the fan threshold temperature set at 60°C. With this setting the fan
will remain at its "ultra low" speed of 1900 rpm and only start ramping up if
the processor temperature exceeds 60°C. During all my burn-in and benchmark
testing the fan never went over this threshold.
Unfortunately I was not able
to see any temperatures, voltage readings or fan speed readings while in Windows
due to the lack of temperature monitoring software support for this new ATI chipset. Shuttle was not able to provide any proprietary monitoring software
either which meant that I was basically in the dark, temperature-wise during
all my testing with the ST62K. All I know for sure is that the CPU temperature
never exceeded 60°C at a room ambient temperature of 21°C.
I tried booting
immediately into the BIOS after running a CPU-intensive app to check the BIOS
temperatures (which do show up, so the sensors are there, they just aren't any
use with any existing Windows-based monitoring applications) but by the time
the system got into the BIOS the CPU temp usually read somewhere in the low
to mid 40°C range. This method is completely worthless for obtaining any
accurate temperature measurements and this situation needs to be addressed.
These SFF systems usually run fairly warm, and even though the ST62K is one
of the best designed of any of them, the user should still be able to monitor
their temperatures so they know how their system is running. It's probably even
more important if one is trying to make the ST62K as quiet as possible, because
the fan speed will most likely be turned down as low as possible, giving the
least amount of cooling available.
Temperature concerns aside, the ICE fan is a very quiet fan at the "Ultra-Low"
1900rpm (actually about 1600rpm according to the BIOS Health Monitor screen)
setting. My sample had a very slight whine and a small amount of air noise.
It had no mechanical clicking noise, nor did it change speed at any time while
I was using the system. The closest comparison for me is
a 92mm Panaflo L1A running at about 6-7 volts. It's also not that far off from a Panaflo 80mm L1A at maybe 8~9V. The rubber-damped mount/shroud
seemed to contribute no resonance or vibration noise of its own either. All told, a
very quiet and effective cooling system on this ST62K. It's by far and away
the quietest Shuttle XPC I've ever heard.
External Power Supply
Along with the single fan ICE cooling system, the new 180W external
power supply plays a giant part in the very low noise of the ST62K. One of the
biggest stumbling blocks of almost all SFF systems are noisy, actively
cooled PSUs that add extra noise and heat to the case. Shuttle's ingenious
solution here is to move the PSU out of the case entirely and make it passively
cooled. Doing away
with the typical, horrifically noisy 40mm active cooling fan on the PSU itself
is another masterstroke by Shuttle. They've managed to design a passively cooled
PSU that only runs slightly warm to the touch, even after extended sessions
of full load benchmarking.
The PSU itself measures about 7" x 5" x 2" and
is connected to the mains by a standard IEC power cord. The connection from
the PSU itself to the motherboard is via a proprietary 6-pin connector. It is a univeral AC input design; it will run correctly on any voltage from 100-240VAC, 50~60 Hz. The output is +12V only, rated at 15A or 180W. Obviously, like most external power supply designs, a good portion of the functions of a standard PSU (such as splitting up the various voltage lines) have been moved on to the motherboard.
PSU, although not small, is easy enough to stash out of the way underneath a
desk or in a corner and it runs so surprisingly cool that I doubt ventilation
is any concern. Set it in a corner and forget it. It makes no noise that I could
hear, other than a very faint hum that's inaudible from over a foot away, and it barely gets warm even under heavy use. What a wonderful design!
Of course some people will complain that it's "only"
a 180W PSU and will not be powerful enough to run a modern, high powered P4
system. To them I say "balderdash!" The lack of a AGP slot means there
will be no power-hungry video cards in this system and you're limited to two
hard drives and one optical drive at best so there just won't be a heavy load
put on this system. My setup ran a P4 2.4C CPU, one 7200 rpm HDD and a 40x Plextor
CD-RW drive. Using a Kill-a-Watt meter to measure the total current draw of this
system, I got readings of 45W total while idling/surfing the web, and 103W total
under full load of 2 instances of CPUBurn. 103W maximum. That still gives you
a very nice cushion before you'll need to worry about running this PSU out of
I chose to use the P4 2.4C CPU, 2 x 512MB of Corsair PC3200
memory and 80GB Seagate Barracuda IV hard drive from my main computer to build
up this system. I did this so I could compare the performance of the IGP 9100
chipset against the 875P chipset and ATi Radeon 7500 vidoecard in my main system.
The build was super-easy and I didn't have any trouble with tight
component access or anything else related to the small footprint of the ST62K
chassis. Even though the 5.25" and 3.5" drive bays aren't removable,
I was able to get excellent access to the CPU socket and DIMM slots by removing
the slide-out hard drive tray. The CPU was easy to install, as was the ICE cooling
unit. The clamp that holds the heatsink to the retention bracket is quite well
designed and very easy to snap into position. The four thumbscrews that fasten
the ICE fan shroud to the chassis made it a easy to bolt it into position. The
two sticks of memory were a snap to install, sliding fairly easy into each DIMM
slot. Many DIMM slots seem to be extra tight but the set on this Shuttle board
didn't require tons of force to fully seat the RAM.
The hard drive was also
easy to install. Simply bolt it into the drive tray, slide the drive tray into
it's slots and tighten the whole assembly down with the handy thumbscrew. Shuttle's
custom 2" long IDE cable and pre-located power connector made
connecting the cables super easy. The optical drive was also very easy to mount
after removing the blank face plate. The drive bolted nicely into position,
and again, Shuttle's pre-located IDE and power cables made connecting it up
a real breeze.
And that's it! Finished. It took longer to write that then it
did to actually do it. It's the easiest system I've ever built. This "barebones"
thing is pretty nice. No board to install, no I/O shield, no front connectors
to puzzle out, No tiny USB 2.0 pins to fret about, no front audio connector
to try and hookup to the correct headers. Literally, the most time-consuming
task of the whole build was applying the thermal compound to the CPU.
Complete! Notice the lack of cable clutter.
This is all thanks to Shuttle's design work.
Fired it up for the first time and dang, that ICE fan is a screamer
at full rpm, which is what it does prior to being controlled by the "Smart
Fan" BIOS setting. Within a few seconds after the BIOS loads, the fan speed drops to the preset
rpm and the screaming stops.
I went right into the BIOS and double-checked various
setting, made a few changes to thing like setting the memory timings to 2-3-3-6,
verifying that the FSB was at 200MHz and Hyper-Threading was enabled. I also
poked around in the Advanced Chipset screen looking at the FSB overclocking
and Vcore settings. The maximum FSB adjustment is only up to 215MHz, a rather
meager 7.5% overclock but that's of no particular issue to me. There is no PCI/AGP
lock but that's also not an issue as 7.5% out of spec shouldn't hurt anything.
One of the coolest things I noticed was that not only was the Vcore adjustable
to a relatively low maximum of 1.5875V, it was also adjustable downwards
to .825V! Now this is something to get excited about! This is an eminently undervoltable board! There are very few undervoltable P4 boards, which is a shame because these
CPUs will run on considerably less than default Vcore. The lower voltage
you apply to the CPU, the cooler it runs. The cooler it runs, the less cooling
fan you need and the cooler the case stays. Less heat is pumped into the case
so you can run a slower, quieter case fan. This is all wonderful if you
are trying to make your system as quiet and cool as possible. For now I left
it at it's default, which for this particular CPU is 1.525V.