AOpen i915Ga-HFS ATX Pentium M Motherboard

Our review examines AOpen’s first full-sized Pentium M board , which aims at the high performance media PC market. (Particularly the Japanese media PC market.) Based on the i915G chipset, this board features no fewer than five video outputs, support for dual channel DDR2, and Azalia 7.1 channel on-board audio. Small noisy heatsinks and some odd issues…

March 31, 2006 by Devon
Cooke

Despite the well publicized popularity of the Pentium M on the desktop platform,
there are surprisingly few consumer desktop boards with the unique Socket 479 that
supports it. One company, AOpen, has been responsible for most of these boards. The i915Ga-HFS is their latest, and it is probably
the most conventional Socket 479 desktop board yet.

It’s a high performance, full-ATX design based on the Intel 915G desktop chipset with full support for dual-channel DDR2 memory. AOpen’s
earlier efforts were smaller Micro-ATX boards; the very first one was based on a mobile chipset.
This board is laid out in a more conventional manner, with the CPU socket near the
top of the board and the RAM DIMMs positioned vertically behind it. Perhaps
because it shares so much of its design with its immediate predecessor, the micro-ATX i915GMm-HFS, it’s
also slightly cheaper, although it still comes
at a significant premium compared other similarly featured boards for other
processors.

The board appears to be aimed squarely at the home theater market — it
comes with an extensive selection of audio and video connectors. That, in conjunction
with the low heat output of the Pentium M, does make the i915Ga-HFS an excellent
candidate for use in an HTPC.

The motherboard and the mandatory dongles and doodads that come with it.

Unfortunately, the painfully obvious presence of a small fan on the northbridge
heatsink does not bode well for noise. Its presence is made especially
odd because none of AOpen’s other Socket 479 boards have used active cooling
for the northbridge.

Even worse, AOpen has once again gone with a proprietary mounting system for
the CPU heatsink, meaning that aftermarket heatsinks (with one exception) cannot
easily be used.

A conventional layout compared to previous models compatible with the Pentium
M.
Click image for a higher resolution view.

FEATURE HIGHLIGHTS

For a board that costs more than US$200, the feature list for the i915Ga-HFS
seems a bit short. As mentioned, the bulk of the features are aimed
at the home theater market. No less than five different video-out connectors
are included, as well as full 7.1 surround jacks for audio, although the jacks
are not the RCA connectors used by most A/V equipment. Surprisingly, S/PDIF
audio is only supported through an internal header — for which no external
bracket is provided.

The lack of easy S/PDIF support is quite a serious omission, at least in the US or Canada. It’s hard to imagine
anyone using a set of computer speakers in a serious home theater system, but
it’s possible that in Japan, AOpen’s primary market for this product, there may be better options than we typically see here. Without S/PDIF it is difficult to hook up an external receiver. Anyone
wanting to connect the i915Ga-HFS to an existing speaker system will need to
purchase a separate S/PDIF adapter. This could be difficult for an end user, but it would have been easy for AOpen to include with the motherboard.

Luckily, there should be no problem hooking up multiple displays. The following
video connections are supported:

• VGA
• DVI
• S-Video (no S-Video to Composite dongle is included)
• RCA-Component Video
• D4-Component Video

With the exception of the D4 connector, all of these should be familiar. The
D4 connector
is a single-plug connector that carries a standard component video signal. It
is used only on Japanese A/V equipment, and does not seem to be slated for worldwide
adoption.

It is far from clear how well these five connectors function in conjunction
with each other. AOpen has helpfully included a table in the manual that is
supposed to show what combinations are valid, but the table is either wrong
or incomplete, as it conflicts with the textual information. It would appear
that a maximum of two independent pictures are supported at any given time,
but it’s not clear whether the same picture can appear on multiple displays
and, if so, in what configurations.

Lots of Video connectors, but no PS/2 or S/PDIF connectors.

To make room for all of the video connections, almost all of the “legacy”
ports have been removed from the rear panel. That means no parallel port, no
serial ports… and no PS/2 ports. There is an internal header for a parallel
port, but adapters that allow them to be attached to a standard cable can be
quite hard to come by. Fortunately, a PCI bracket for a PS/2 keyboard is included,
but anyone still using a PS/2 mouse is out of luck — the only PS/2 header
is wired for use with just a keyboard.

Another common feature that’s missing is RAID support. This is
quite odd, as AOpen’s previous i915GMm-HFS
did support RAID, despite having only two SATA connectors. It is another feature
that may be missed in a home theater PC, since a large amount of video storage
is easier to manage as a single RAID 0 array than as multiple volumes across
several drives. That said, remote storage is often a more practical solution
than trying to jam all that storage into a small HTPC case.

For a full ATX board, the number of expansion slots — 3 PCI plus one 16x
PCI Express — is quite limited. What, no 1x PCIe, you say? True, there
is a physical slot included on the motherboard, but take a closer look at the
photo below. Notice how the bottom edges of the two PCI express slots (black and orange) don’t
align with each other? What you see here is known in the business as a…
mistake. AOpen has admitted bravely in their FAQ for the board that the misalignment makes the slot unusable…

“Q7287: Does i915Ga-HFS support PCIe x1?
No, for some mechanical issue with the PCIe x1 slot on this motherboard, it will not support PCIe x1 devices. We will also cancel the slots in the future. Truly sorry for the confusing.”

…and removed the slot from the spec sheet. Hopefully, their quality control
has been adjusted to catch future instances as well.

The PCIe 1x slot should be aligned with the 16x slot on the left, not the
PCI slot on the right.

HEATSINKS AND COOLING

Cooling for the i915Ga-HFS is provided by two smallish aluminum
heatsinks: One for the northbridge and one for the CPU. AOpen has been faulted
in the past for the noise of their heatsink fans and the lack of a standard
mounting system for the CPU heatsink. Unfortunately, the nonstandard mounting
system is back, but the heatsink appears to be identical to the revised (and
much quieter) heatsink that shipped with later versions of the i915GMm-HFS.

Two smallish fans make for double the potential noise levels.

The new northbridge fan introduces yet another source of noise
into the system. Neither the fan nor the heatsink itself is very large, but
it’s probably big enough to cool the basic northbridge. Whether or not it can
do it quietly remains to be seen.

The fins on the northbridge heatsink are quite rudimentary.

The CPU heatsink is a simple all-aluminum design, but it is tall enough that
it should handle any of the 27W Pentium M chips out there. The fins are not
especially tight, which bodes well for low airflow performance.

The fan snaps off easily.

The base of the heatsink is just barely wide enough to cover the
CPU socket, which is rotated 45° relative to the rest of the motherboard.
Because the socket is not quite square, the CPU is not quite centered under
the heatsink. Extra care should be taken during installation to ensure that
the base of the heatsink lies flush against the CPU die.

The slightly oblong shape of the CPU socket positions the CPU slightly off-center
relative to the base of the heatsink.

Fortunately, there is a square pad on the base of the heatsink
that is designed to rest evenly on the surface of the processor PCB and equalize
the pressure from all sides.

The mounting system is a simple backplate and four spring-loaded
screws. The correct tension (or what we assume is the correct tension) is obtained
by gradually tightening all of the screws together until none of them will turn
any more. Overtightening, as we learned from experience, can lead to stripping
the nut in the backplate, making for a very difficult to remove heatsink (pliers
were required).

The mounting system.

BIOS

In a Pentium M system, the BIOS settings are almost irrelevant.
The extremely low heat output means that a quiet constant speed fan can be used
on the CPU heatsink without worrying about things overheating under load. Likewise,
there is little point in underclocking or undervolting, especially considering
that the Pentium M’s power consumption at idle drops
below a single watt when SpeedStep is enabled.
AOpen is seems to be gambling on this point, as no adjustment of the CPU voltage
is possible. This has been a point of complaint for overclockers, but silencers
are unlikely to miss it. That aside, the usual range of FSB and multiplier adjustment
is available, along with basic voltage controls for some of the onboard peripherals.

The fan controller is a bit more advanced: Three options are given:

• Full Speed
• Smart Control, which allows a thermal target to be set
• Fixed Speed, which controls the speed of the fan as a percentage of the
  fan’s maximum speed

These options can be set independently for the “system fan” (actually,
the northbridge fan) and the CPU fan. The Smart Control mode also functions
as a way of disabling the fan speed alarm that inevitably goes off if a fan
is undervolted or — even worse — externally controlled. Each fan can
be set to maintain a target temperature appropriate for the thermal sensor that
controls it. The range of adjustment is as follows:

• CPU Fan: Disabled, or 25~70°C in five degree increments
• System Fan: Disabled, or 30~40°C in five degree increments

Three fan control modes offer plenty of choice.

Target temperature for the CPU can range up to a toasty 70°C (this is
the target we chose).

In addition to the thermal protection offered by the fan, there are a number
of other options selectable in the BIOS. SpeedStep can be enabled or disabled
by choosing to enable “Thermal Monitor 1” (CPU throttling) or “Thermal
Monitor 2” (SpeedStep). A CPU Warning temperature can also be set to trigger
an alarm and automatic throttling if the CPU exceeds a certain temperature.

A warning alarm can be set to go off if the CPU exceeds a certain temperature.

The FSB allows more overclocking that is reasonably attainable.

The multiplier (not CPU Bus Frequency as the title might suggest) can also
be adjusted, but only downwards.

True to its status as a home theater board, there is also an option that allows
the exact TV format that is output by the board. A total of 20 different formats
are supported, all variants of NTSC, PAL and SECAM. Most users will just want
to leave this on auto, but users with multi-format televisions may want to tweak
this option to use the best format for their source. There is also some potential
for rough-and-ready standards conversion by connecting the TV out directly into
a capture card that can read the appropriate format.

All these standards plus 13 more are supported.

ON THE TEST BENCH

Methodology

The following components were used with the motherboard:

• FSP Green PS FSP400-60GLN 400W power supply — 69.7%
  efficient at 40W output, 75.8% efficient at 64W output,
• Intel Pentium M 770 — 2.13 GHz, 27W TDP
• 2 x 1024 MB Corsair DDR2 SDRAM
• Hitachi E7K100 — 100GB, 7,200 RPM notebook hard drive

These tools were used to make measurements during testing:

• AC Power was measured with an Extech Power Analyzer / Data Logger 380803
  AC power meter.
• Processor temperature was monitored using AOpen’s PowerMaster utility, as
  SpeedFan 4.27
  did not work.
• SPL was measured with a B&K 2203 Sound Level Meter.
• CPUBurn
  was used to place the processor under load while thermal and acoustic testing
  was done

The goal of the testing was to find out how much (or how little) noise is produced
by the motherboard in its stock form. Every effort was made to optimize the
BIOS settings for low noise operation, so both the CPU and the Northbridge fans
were set to Smart Control at the highest possible trigger temperature. Noise
measurements were then made with the system at idle and under heavy CPU load,
and the processor temperature was monitored to ensure that it did not overheat.

The ambient conditions during testing were 20 dBA and 21°C.

Test Results

Unfortunately, our careful tweaking of the fan settings in the BIOS all came
to naught within a minute of pressing the power button; as soon as Windows finished
loading, both fans immediately rose to maximum speed and stayed there indefinitely.
No amount of tweaking settings in the BIOS (including turning the fans off altogether)
could prevent this inevitable result, so we eventually concluded that Windows
XP was overriding the BIOS settings entirely.

Our backup plan was to use AOpen’s Windows-based SilentTek
utility to control the fans, but here, too, we ran into problems. Running the
fan control software required a calibration process to
determine the range of adjustment for each of the connected fans. Unfortunately, the result of
the calibration only allowed adjustment between 90% and 100% speed —
not enough to make an audible difference.

Eventually, we ended up measuring the noise level
with the fans at full speed. Unsurprisingly, the noise level is too high to
be considered quiet. However, in acknowledgment of the fact that the fans really
shouldn’t be running at full speed, we also took some hasty measurements
while the BIOS was controlling the fans before Windows had finished booting.

As the table shows, the i915Ga-HFS was at its quietest while the BIOS fan controller
was still working. In fact, the northbridge fan turned off altogether in this
state, leaving the CPU fan as the only source of noise. At this level, the noise
level was quite low, consisting mostly of a low hum that disappeared into
the whoosh of airflow as we moved away from it.

Unfortunately, the noise became nasty as soon as Windows finished loading.
The bulk of the noise came from the tiny northbridge fan which produced a rough
buzzzzzz in the frequency range humans are most sensitive to.
A harmonic overtone could also be heard from time to time as a shrill whine
in the background. Temporarily stopping the CPU fan had very little effect on
the overall noise level, which suggests that most of the noise is from the
northbridge fan alone.

Naturally, we wanted to know what the board would sound like without the northbridge
fan, so we stopped it temporarily and listened to the CPU fan on its own. Much
to our surprise, the noise of the CPU fan at full speed was quite bearable, though far from
silent. The CPU fan was quite smooth and constant, although it was too pure
a tone to ignore completely.

Not surprisingly, the CPU temperature at idle approached the ambient room temperature.
In fact, it would have been surprising if it had been significantly higher,
given that the power consumption of the CPU
with SpeedStep enabled is ~1.0W.

The real test was the temperature under load, which topped out at 61°C
— surprisingly high given that the fan was running at full speed. A quick
finger test confirmed that the heatsink was indeed too hot to touch for more
than a few seconds. No throttling was ever observed, however, and the system remained
stable throughout several hours of extensive thermal testing.

A few words of caution about the thermal results: The thermal diode on the
motherboard was not calibrated beforehand, and its very rapid changes suggest
that the reported temperature may be something different than what
most motherboards report (a diode that approximates exterior casing temperature). Additionally, a second
sample of the i915Ga-HFS reported a temperature as much as 10°C
different from those above with the same CPU (when all other factors were held constant). Hence, take the temperature
data above with a grain of salt.

FINAL THOUGHTS

Much thanks to AOpen
for the opportunity
to review this motherboard.

* * *

Articles of Related Interest

• AOpen i915GMm-HFS: 2nd Gen P-M desktop board
• Pentium M for the Desktop: AOpen i855GMEm-LFS and DFI 855GME-MGF
• AMD Turion 64 on the Desktop
• Microcool NorthPole XE Whisper heatsink/fan
• Shuttle SD11G5 Pentium M SFF barebones PC

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