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Asus M4A78-HTPC/RC: A Complete HTPC Solution?

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The Asus M4A78-HTPC/RC is one of many AM2+ motherboard based on the 780G chipset. Asus has thrown in a few extras to differentiate it from the crowd – as you can guess by the model number, the board is aimed specifically at the HTPC market.

Asus M4A78-HTPC/RC

May 31, 2009 by Lawrence Lee

Product Asus M4A78-HTPC/RC
AMD AM2+ Motherboard
Manufacturer ASUSTeK
Street Price US$??

More than a year after its launch, AMD’s 780G
has lost a bit of its luster. In computer time, it has become just about venerable. Though no longer the exciting,
game-changing IGP it once was, HD 3200 has aged well, being favored today as
an affordable base for budget PCs, and for media centers. When it comes
to home theater PCs, there are few, if any reasons to use a more expensive chipset like 790GX. All a HTPC really
needs is good high definition video/audio playback and plenty of digital outputs.

The box.

Asus decided to capitalize on this notion by releasing a board specifically
aimed at the HTPC market. The M4A78-HTPC/RC is an AM2+ motherboard based on
the 780G chipset and ships with an IR remote and receiver. The remote is to
interface with "Home Theater Gate," the Asus equivalent of Media Center.
A few extra features are also thrown in an attempt to appeal to audiophiles
including gold-plated RCA connectors, an auxiliary power connector for the audio
system that Asus claims will reduce electrical noise, and "DTS Surround
Sensation" which simulates multi-channel sound on stereo speakers and headphones.
Asus also sells the M4A78-HTPC, the same board minus the remote.


Asus M4A78-HTPC/RC: Specifications (from the
product web page
CPU AMD Socket AM2+ / AM2 Phenom™
X4/Phenom™ X3/Athlon™ /Athlon™ X2/Sempron™ Processors
Support AM3 Phenom™ II / Athlon™ X4 / Athlon™ X3 / Athlon™
X2 Processors
AMD Cool ‘n’ Quiet™ Technology
Support 45nm CPU
Chipset AMD 780G/SB700
System Bus Up to 5200 MT/s for AM3
2000 / 1600 MT/s for AM2 CPU
HyperTransport™ 3.0
Memory 4 x DIMM, Max. 16 GB, DDR2
1066/800/667 ECC,Non-ECC,Un-buffered Memory
Dual Channel memory architecture

*Due to AMD CPU limitation, DDR2 1066 is supported by AM3/AM2+ CPU for one
DIMM per channel only.
**Due to OS limitation, when installing total memory of 4GB capacity or
more, Windows® 32-bit operation system may only recognize less than
3GB. Hence, a total installed memory of less than 3GB is recommended.
***Refer to www.asus.com or the user manual for the Memory QVL (Qualified
Vendors Lists)

Expansion Slots 1 x PCIe 2.0 x16
2 x PCIe x1
1 x PCI 2.2
VGA Integrated ATI Radeon™
HD 3200 GPU
Max. shared memory: 256 MB
– Supports HDMI™ Technology with max. resolution up to 1920 x 1200
– Supports Dual-link DVI with max. resolution up to 2560×1600 @60Hz
– Supports D-Sub with max. resolution up to 2560×1440 @75Hz for 16:9 format
– Hybrid CrossFireX™ Support
– Dual independent displays support with HDMI/DVI and D-Sub
– Supports Microsoft® DirectX 10, OpenGL 2.0, Pixel Shader 4.0
– Hardware Decode Acceleration for H.264, VC-1, and MPEG-2
Storage SB700 Chipset
1 xUltraDMA 133/100/66 for up to 2 PATA devices
5 xSATA 3 Gb/s ports Support RAID 0,1,10
1 x external SATA 3Gb/s ports
** Due to the Windows XP/ Vista limitation, the RAID array with the total
capacity over 2TB cannot be set as a boot disk. A RAID array over 2TB
can only be set as a data disk only.
LAN Atheros L1E Gigabit LAN
controller featuring AI NET 2
Audio 8 -Channel High Definition
– Supports Jack-Detection, Multi-Streaming
– Coaxial and Optical S/PDIF Out ports at back I/O
– DTS Surround Sensation Ultra PC
– 2-ch Gold-plated RCA output at back I/O
– ASUS Noise Filtering
USB 10 USB 2.0 ports (6 ports
at mid-board, 4 ports at back panel)
ASUS Unique Features ASUS HTPC Features
– ASUS Absolute Pitch Hi-Fi
– ASUS Home Theater Gate
– ASUS Tranquil Mode (for AM3/AM2+ CPU only)
– DTS Surround Sensation Ultra PC
ASUS Quiet Thermal Solution
– ASUS Fanless Design: Soundwave Heat-sink solution
ASUS Express Gate
– ASUS Q-Connector
– ASUS CrashFree BIOS 3
– ASUS EZ Flash 2
– ASUS MyLogo 2
Overclocking Features Precision Tweaker
– vCore: Adjustable CPU voltage at 0.05V increment
SFS (Stepless Frequency Selection)
– FSB tuning from 200MHz up to 550MHz at 1MHz increment
– PCI Express frequency tuning from 100MHz up to 150MHz at 1MHz increment
– GPU tuning from 500MHz up to 999MHz
Overclocking Protection
– ASUS C.P.R.(CPU Parameter Recall)
Back Panel I/O Ports 1 x DVI
1 x D-Sub
1 x HDMI
1 x External SATA
4 x USB 2.0/1.1
8 -Channel Audio I/O
1 x Coaxial S/PDIF Out
1 x Optical S/PDIF Out
2-ch RCA audio output connectors
Internal I/O Connectors 3 x USB connectors (6 ports)
1 x IDE connector
5 x SATA connectors
1 x CPU Fan connector
2 x Chassis Fan connector
1 x Power Fan connector
1 x S/PDIF Out connector
Front panel audio connector
System Panel
CD audio in
24-pin ATX Power connector
4-pin ATX 12V Power connector
4-pin ATX 12V Audio power connector
BIOS 8 Mb Flash ROM
AMI BIOS, PnP, DMI2.0, WfM2.0, SM BIOS 2.5, ACPI 2.0, ASUS EZ Flash 2
Accessories User’s manual
1 x UltraDMA 133/100/66 cable
1 x SATA cable
I/O Shield
2 in 1 Q-connector (USB, System panel; Retail version only)
ASUS Home Theater Gate Remote Controller set
Support Disc Drivers
Express Gate
Anti-virus software (OEM version)
ASUS Update
ASUS Home Theater Gate
Form Factor uATX Form Factor
9.6 inch x 9.6 inch ( 24.4 cm x 24.4 cm )


A board’s layout is important in several regards. The positioning of components
can dictate compatibility with other products (third party heatsinks mainly)
and also ease of installation. Poorly placed power connectors can also disrupt
airflow and make the system more thermally challenging.

The board’s layout is fairly orderly.
The main ATX power connector is located on the right side of the board
above five SATA ports and a single IDE connector at right angle
to the PCB. A molex connector is located at the very bottom of the board
under the PCI slot to give the onboard audio an independent supply of

The northbridge cooler is good sized and short enough to avoid
problems for third party CPU coolers. The southbridge heatsink, as typical
on Asus boards, is diminutive. Asus has also covered it with a decorative
plate depicting an equalizer graph making it more difficult to dissipate
heat. The voltage regulators to the left of the CPU socket are bare.

The back panel is stocked with everything one would expect to see on a
HTPC-oriented board including HDMI, S/PDIF, and the aforementioned gold-plated
RCA audio ports. There is also a sticker urging us to connect the included
remote receiver to one of two specified USB ports.

The board with an Arctic Cooling Alpine 64 heatsink installed.


For enthusiasts, the options available in the BIOS can make
a good board a great one. The ability to manipulate frequencies, voltages,
and fan control settings vary depending on the hardware and the amount of
trust placed in the user’s hands by the manufacturer.

Frequency/Voltage options. Voltage tweaks are severely limited and no
undervolting is possible.

More Frequency/Voltage options. Minor adjustments can be made to chipset/SB

"Hardware Monitor." Q-Fan control is available for both CPU
and Chassis fans.

BIOS Summary
CPU Frequency
200 MHz to 500 MHz
CPU Voltage +50 mV, +100 mV, +150 mV
Overclock Options
2%, 5%, 8%, 10%
Memory Frequency
Athlon X2 4850e – 667 MHz, 800 MHz
Phenom II X3 720 – 667 MHz, 800 MHz, 1066 MHz
Memory Timing Control
Memory Voltage
1.800V, 1.900V, 2.000V, 2.100V
Processor-Northbridge Voltage
+50 mV, +100 mV, +150 mV
Chipset Voltage
1.1V, 1.2V, 1.3V, 1.4V
Southbridge Voltage
1.1V, 1.2V
Integrated Graphics
GPU Clock
150 MHz to 999 MHz (500 MHz default)
UMA Frame Buffer
32MB, 64MB, 128MB, 256MB,
Fan Control
CPU Fan Type PWM or DC Fan
CPU Q-Fan Mode
Performance, Optimal, Silent
Chassis Q-Fan Mode
Performance, Optimal, Silent

Overall the BIOS is much more restrictive than most 780G boards.
As CPU voltage can only be increased, and by only a small amount at that,
the M4A78-HTPC/RC is a poor choice for both overclocking and underclocking.
It’s fine for HTPC, but a bit of extra
versatility wouldn’t have hurt.


Test Setup:

Measurement and Analysis Tools

  • CPU-Z
    to monitor CPU frequency and voltage.
  • CPUBurn

    processor stress software.
  • Prime95
    processor stress software.
  • ATITool
    artifact scanner to stress the integrated GPU.
  • FurMark
    stability test to stress the integrated GPU.
  • Cyberlink
    to play video.
  • SpeedFan
    to monitor temperature and fan speeds.
  • Seasonic
    Power Angel
    AC power meter, used to measure the power consumption
    of the system.
  • Custom-built, four-channel variable DC power supply, used to regulate
    the CPU fan speed.

Our main test procedure is designed to determine the overall system power consumption
at various states (measured using a Seasonic Power Angel). To stress Intel Pentium
E/Core 2 CPUs we use Prime95 (large FFTs setting) to maximize heat and power
consumption. For AMD X2 CPUs we use CPUBurn K7 as it seems to tax AMD processors
more. To stress the IGP, we use ATITool artifact scanner, ATITool 3DView, or
FurMark, whichever application is found to be more power hungry.

We also test platform’s proficiency at playing back high definition videos.
Standard Blu-ray movies can be encoded in three different codecs by design:
MPEG-2, H.264/AVC and VC-1. MPEG-2 has been around for a number of years and
is not demanding on modern system resources. H.264 and VC-1 encoded videos on
the other hand, due to the amount of complexity in their compression schemes,
are extremely stressful and will not play smoothly (or at all) on slower PCs,
especially with antiquated video subsystems.

Our main video test suite features a variety of 1080p H.264/VC-1 encoded clips.
The clips are played with PowerDVD and a CPU usage graph is created by the Windows
Task Manger for analysis to determine the approximate mean CPU usage. High CPU
usage is indicative of poor video decoding ability on the part of the integrated
graphics subsystem. If the video (and/or audio) skips or freezes, we conclude
the board’s IGP (in conjunction with the processor) is adequate to decompress
the clip properly.

Cool’n’Quiet was enabled (unless otherwise noted). The following features/services
were disabled during testing to prevent spikes in CPU/HDD usage that are typical
of fresh Vista installations:

  • Windows Sidebar
  • Indexing
  • Superfetch

Video Test Suite

1080p | 24fps | ~10mbps
Rush Hour 3 Trailer 1
is a H.264 encoded clip inside an Apple
Quicktime container.

1080p | 24fps | ~8mbps
Coral Reef Adventure Trailer
is encoded in VC-1 using the
WMV3 codec commonly recognized by the "WMV-HD" moniker.

1080p | 24fps | ~19mbps
VC-1: Drag Race is a recording of a scene from
network television re-encoded with TMPGEnc using the WVC1 codec, a
more demanding VC-1 codec.

1080p | 24fps | ~33mbps
Blu-ray: Disturbia is a short section of the
Blu-ray version of Disturbia, the motion picture, played directly
off the Blu-ray disc. It is encoded with H.264/AVC.


Our test system is fairly basic, featuring a X2 4850e (a budget dual core processor
with a low 45W TDP) cooled by an Alpine 64 cooler, a single 1GB stick
of Corsair memory, an Asus Blu-ray drive and a 5400RPM notebook hard drive,
all powered by an 80 Plus OEM Seasonic 400W power supply.

Test Results: X2 4850e @ 2.5GHz (C&Q)
Test State
System Power
Rush Hour
Coral Reef
Drag Race
(Blu-ray H.264)
CPU Load

The M4A78-HTPC/RC is one of the more energy-efficient AMD motherboards we’ve
tested. Our test system idled at only 34W, and stayed under 60W when playing
H.264 and WMV-HD. VC-1 and Blu-ray playback pushed it closer to 70W. Power draw
with the CPU fully stressed was 88W with another 8W on top when the IGP was
pushed. As the HD 3200 IGP is still formidable by today’s standards, it passed
our playback tests with relative ease, only being challenged by our high bitrate,
high resolution 1080p VC-1 clip.

Test State
M3A78 Pro
Mean CPU
System Power
System Power
System Power
Rush Hour
Coral Reef
Drag Race
CPU Load
CPU + GPU Load

As it turns out, the M4A78-HTPC/RC is among the lowest power AMD boards we’ve
encountered, coming close to matching the Gigabyte’s 740G-based board in idle
power consumption. Power draw on load was also excellent, as most of the AM2+
mainboards we’ve tested use more than 90W when the CPU is stressed, and sometimes
100W+ or more when the GPU is put on load as well.

CPU usage during video playback, as expected, was similar to the M3A78 Pro,
another of Asus’ 780G motherboards, though the M4A78-HTPC/RC used less energy during
playback with the 1080p VC-1 clip being the exception.

AM3 CPU Power Consumption

In our M4A78T-E review,
we noticed a significant power consumption discrepancy of up to 22W when using
an AM3 CPU on an AM2+ motherboard. Unfortunately the M4A78-HTPC/RC is also afflicted
by this anomaly, so it doesn’t appear to have been an isolated case.

Power Consumption: Phenom X3 720 (AM3)
Test State
M4A78-HTPC (780G AM2+)
(790GX AM2+)
M4A78T-E (790GX AM3)
CPU Load
Systems configured with 2GB of RAM and 256MB IGP

Using a Phenom II X3 720 processor, our test configuration’s idle power was
similar to 790GX based M4A78T-E (AM3). Once any type of stress was placed on
the system, the board drew significantly more power as measured from the wall.
During video playback, we measured a 20W difference. This figure expanded to
30W when the CPU was placed on load. The results were similar to what we found
with the M3A78-T, only the
difference was even more pronounced, possibly due to poorer power regulation.
We’ve always found that high TDP chips tend to generate higher power consumption
on budget chipsets lacking in VRM cooling.


Lower cost boards ship with simple heatsinks on the northbridge and southbridge
while those targeted at enthusiasts typically have large heatpipe coolers and
heatsinks on the voltage regulation modules near the CPU socket. A well-cooled
motherboard can deliver better power efficiency and stability.

Heatsink Temperatures
Measuring Point
X2 4850e
X3 720
SB Heatsink
NB Heatsink
Measured with a spot thermometer after 10 minutes
of full CPU + GPU load. CPU fan reduced to 6V.

The cooling on the board was very good when used with the X2 4850e processor.
The hottest spot on the northbridge and southbridge heatsinks measured 51°C
and 45°C respectively, while the VRMs registered in the low 50’s. With a
Phenom II installed, we recorded significant increases in heatsink temperature,
though we could still place our fingers on them comfortably for long periods
of time. The VRMs, on the other hand, were burning hot — some extra cooling
here would not be amiss.

BIOS Fan Control

We tested the board’s fan control by connecting the CPU cooler’s fan to a variable
DC fan controller, so we could lower it as necessary, and proceeded to stress
the processor using Prime95 while monitoring fan speeds using PC Probe. A Scythe
92mm PWM fan (2500 RPM) was connected to the CPU_FAN header, a Scythe Kama Flow
80mm 3-pin fan (1600 RPM) to the CHA_FAN1 header, and a Nexus 92mm 3-pin fan
(1400 RPM) to the CHA_FAN2 header.

Fan Control Results (Silent mode)
Test State
Min. Speed
660 RPM
420 RPM
490 RPM
Max. Speed
2450 RPM
1610 RPM
1350 RPM
Trigger Temp.
Temp. Range

Q-Fan in Silent mode produced very good fan control results. All three fans
spun at approximately 25% speed when idle. The CPU fan began increasing in speed
when the temperature reached 44°C and the Chassis fans followed suit at
51°C. It took a 10°C increase before all the fans reached their nominal
speeds. The fan speed progression was fairly smooth.

SpeedFan Support

For Windows, SpeedFan is our application of choice for fan control. It
can be configured to raise or lower multiple fan speeds to designated limits
when any specified temperature threshold is breached.

SpeedFan with correlations entered.

SpeedFan reported the fan speeds of all four of the onboard fan headers. Temp1
matched the CPU temperature readout in Asus Probe, and Temp2 matched "MB"
which, through thermal testing we determined to be related to the temperature
of the southbridge — placing a fan over the southbridge heatsink under
load resulted in a significant decrease in the Temp2 reading.

The CPU and Chassis fans can all be controlled independently through SpeedFan.
Speed01 controls fans connected to the CPU fan header using PWM, while Speed02
works on both PWM and regular 3-pin fans. Speed03 controls the CHA_FAN1 header
and Speed04 controls the CHA_FAN2 header. To enable full fan control, select
the "IT8712F-J" chip in the Advanced tab of the Configuration menu
and set all the PWM modes to "Software Controlled."

Remote Control & Home Theater Gate

The included remote was comfortable and easy to use and had a pretty good range
of about 15 feet, did not require direct line-of-sight, and could be used to
turn on or put the system to sleep. The remote is designed to control Home Theater
Gate, Asus’ version of Media Center.

The software’s main menu is fairly simple, with options for music, video,
photos, and internet radio.

The video menu is the most basic with a simple browse and play interface
and no thumbnail or preview option. Both video and music are played via
Windows Media Player.

The audio menu is slightly more advanced as you can check off tracks to
make a simple play list. There is also a folder you can use as a shortcut
to your favorites.

The photo menu looks more or less like Media Center, though it lacks the
ability to do slideshows.

Once configured, any number of internet radio stations can be played through
Home Theater Gate using the bundled mediaU player.

Using the remote control was simple and intuitive, though Home Theater Gate
is no replacement for Windows Media Center. The menus lack both flash and functionality.
The remote can actually be used with Media Center, but many of the shortcut
buttons are tied to Asus’ software as they are designed to jump from menu to
menu. Unless you plan on playing different types of media at the same time,
it’s probably easier to use it as a Media Center remote.

Audio Features

Providing independent power to the onboard audio via a molex connector did
not result in any increase in power consumption. We noticed a moderate decrease
in static and background noise when the extra power connector was on, but nothing to write home
about. The "DTS Surround Sensation" was not tested as we do not believe
it is a worthwhile feature in this type of product. Most enthusiasts capable
and willing of building a true HTPC will have a real multi-channel sound system,
so synthesizing a multi-speaker setup with stereo speakers would be pointless.
Emulated surround sound is probably more effective with headphones but not many
HTPC users use them. The gold-plated RCA connectors are convenient for stereo
speakers since you do not require an adapter, but the plating itself has little
value outside of preventing oxidation.


The Asus M4A78-HTPC/RC is a very capable motherboard in its own right, i.e.
if we ignore the remote and audio extras. It has plenty of features including
HDMI, S/PDIF, and eSATA, and its heart, the tried and true HD 3200 IGP, is fully
capable of high definition video playback. With SpeedFan, one can fully control three
fans connected to the board independently, or if you prefer the set-it-and-forget-it
option, the board’s automatic fan control system works well too. When paired
with a low TDP processor, it is one of the more energy efficient boards in its
class, both when idle and stressed. It does exhibit high power consumption when
paired with an AM3 chip, but that seems to be a universal problem with all AM2+
motherboards. The BIOS is very restrictive and lacks the ability to undervolt,
so those who like to tinker with their systems to get the lowest power consumption
possible will have to look elsewhere.

With a solid base, Asus added features to cater to the Home Theater crowd.
The included IR remote is simple and intuitive, but the software it is paired
with lacks both polish and functionality. The current version doesn’t hold a
candle to Media Center, though that could change if Asus continues working
on it. If the current version is the best they can do, it might as well have
been shipped the board with a regular MCE remote. You can use the bundled remote
with Media Center, though there are a few buttons that will only work
with Home Theater Gate.

The additional audio functionality is of limited use, in our view. Powering the board’s audio
independently does reduce some static and noise but it falls short of being
a compelling must-have, must-try feature. "DTS Surround Sensation"
has limited value for a board of this type — it is probably better used in
a typical desktop environment with stereo speakers or headphones rather in the
living room with a HTPC. The gold-plated RCA connectors may give the board a
level of cachet but true audiophiles will recognize it as a gimmick.

To summarize, the M4A78-HTPC/RC certainly can be a good base for a home theater
PC, but it is not necessarily our top choice. The core hardware is excellent,
but the extras that differentiate it have marginal value, in our opinion.
If the audio features came at no extra
cost, and the remote was made for use with MCE rather than Home Theater Gate, it would appeal fine.
As it stands, we can pick out any 780G board with the appropriate feature-set and
an MCE remote for functionality just as good as the M4A78-HTPC/RC package Asus is offering. The board will probably not be released in North America, so there is no official price for US/Canada. However, an online search came up with a price of 7,100 Rupees in India and 6,300 Rupees without the remote. That translates currently to ~US$150 and ~US$134, not exactly bargains in North America where mATX 780G board rarely crack $100. IT goods are often priced higher elsewhere, however, so do take our comments about value with caution.

Asus M4A78-HTPC/RC

* Low power consumption
* Independent control of up to 3 fans
* Feature-rich
* Remote works well


* Questionable audio features
* Remote software lacking in capability
* Restrictive BIOS; does not allow undervolting

Our thanks to ASUSTeK
for the motherboard sample.

* * *

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MSI KA760GM: 780G Minus the HD
790GX Showdown: Gigabyte vs. MSI
Zotac GeForce 8200-ITX WiFi: A Compact
AM2 Solution

Asus P5N7A-VM: Geforce 9300

* * *

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