Asus M4A78T-E AM3 motherboard

Table of Contents

The Asus M4A78T-E is an AM3 ATX motherboard based on the 790GX/SB750 chipsets. It is another feature-rich board with integrated graphics, CrossFireX, and support for AMD’s newest AM3 processors. We will be using a X3 720 Black Edition processor for testing and we’ll also plop it into a comparable AM2+ board to see if AM3/DDR3 results in any real-world improvements over AM2/DDR2.

April 4, 2009 by Lawrence Lee

Products Asus M4A78T-E AM3 Motherboard
Manufacturer ASUSTeK
Street Price
(Click to check current price)

At the beginning of the year, AMD made serious strides to catch up to rival
Intel by launching their Phenom II line of CPUs. Though AMD’s new socket, AM3,
was just around the corner, these chips were released in the familiar
AM2+ package, rather than straight to AM3. The fact that AM3 processors
are backwards compatible with AM2+ made the move even more baffling.

AM3 is finally here, and there isn’t a lot to explain. To say it
is a “platform change” is a bit generous — the only thing new AM3
brings to the table is support for DDR3 memory. You may remember that when DDR2
memory started showing up, there was no performance advantage over DDR. Though
DDR2 ran at higher frequencies, this was mitigated by higher latencies. DDR3
suffers from all the same issues, so we’re reluctant to say its a good time
to switch.

The package.

We are looking here at the Asus M4A78T-E, an AM3 ATX motherboard based on the
790GX/SB750 chipset. It is another feature-rich board with integrated
graphics, CrossFireX, and of course, support for the latest AMD processors.
Currently only three AM3 processors are widely available, all belonging to the Phenom
II family: the triple-core X3 710 and 720 running at 2.6GHz and 2.8GHz respectively,
and the quad-core X4 810 clocked at 2.6GHz. We will use a X3 720 Black
Edition, and given its backwards compatibility, plop
it into an AM2+ board to see if there is any practical difference.

Just the bare essentials.


Asus M4A78T-E: Specifications (from the
product web page
CPU AMD Socket AM3 Phenom™
II/Athlon™ X4/Athlon™ X3/Athlon™ X2 Processors
AMD Cool ‘n’ Quiet™ Technology
Supports 45nm CPU
AMD 140W CPU Support
Chipset AMD 790GX/SB750
System Bus Up to 5200 MT/s HyperTransport™
Memory 4 x DIMM, Max. 16 GB, DDR3
1600(O.C.)/1333/1066 ECC,Non-ECC,Un-buffered Memory
Dual Channel memory architecture
*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 for the memory QVL (Qualified Vendors Lists).
Expansion Slots 2 x PCIe 2.0 x16 support
ATI CrossFireX™ technology, at full x16 or dual x8 link
2 x PCIe x1
2 x PCI 2.2
VGA Integrated ATI Radeon™
HD 3300 GPU
SidePort Memory – onboard 128MB DDR3 1333 memory
– 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
– Hybrid CrossFireX™ Support
– Dual independent displays support with HDMI / DVI and D-Sub
– Supports Microsoft® DirectX 10, OpenGL 2.0, Shader Model 4.0
– Hardware Decode Acceleration for H.264,VC-1, and MPEG-2
– Maximum shared memory of 512MB
Storage SB750 Chipset
1 x UltraDMA 133/100/66 for up to 2 PATA devices
5 x SATA 3 Gb/s ports Support RAID 0,1,5,10,JBOD
1 x eSATA 3Gb/s port *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. For more information,
please refer to
LAN Atheros® L1E Gigabit
LAN controller featuring AI NET 2
Audio VIA® VT1708S 8 -Channel
High Definition Audio CODEC
– Supports Jack-Detection, Multi-Streaming, and Front Panel Jack-Retasking
– Optical S/PDIF Out ports at back I/O
– ASUS Noise Filtering
IEEE 1394 VIA® VT6315N controller
supports 2 x 1394a ports (1 at mid-board; 1 at back panel)
USB 12 USB 2.0 ports (6 ports
at mid-board, 6 ports at back panel)
ASUS Unique Features ASUS Power Solutions:
– 8+1 Phase Power Design
– ASUS Anti-Surge Protection
ASUS Green Design:
Express Gate
ASUS Quiet Thermal Solution:
– ASUS Fanless Design: Stylish heat sink solution
– ASUS Q-Fan2
– ASUS Q-Shield
– ASUS Q-Connector
– ASUS CrashFree BIOS 3
– ASUS O.C. Profile
– ASUS EZ Flash 2
Overclocking Features Intelligent overclocking
– AI Overclocking (intelligent CPU frequency tuner)
– TurboV
– Turbo Key
Precision Tweaker 2
– vDIMM: 50 -step DRAM voltage control
– vCore: Adjustable CPU voltage at 0.0125V increment
– vChipset (N.B.): 16-step voltage control
SFS (Stepless Frequency Selection)
– FSB tuning from 200MHz up to 600MHz at 1MHz increment
– PCI Express frequency tuning from 100MHz up to 150MHz at 1MHz increment
Overclocking Protection
– ASUS C.P.R.(CPU Parameter Recall)
Special Features 100% All High-quality Conductive
Polymer Capacitors! (VRM 5000hrs lifespan @105°C, 500,000hrs @65°C)
ASUS MyLogo 2
AMD OverDrive Support*
*Advanced cooling system is required when advanced overclock functions of
AMD OverDrive are enabled.
Back Panel I/O Ports 1 x DVI
1 x D-Sub
1 x HDMI
1 x External SATA
1 x S/PDIF Out (Optical)
1 x IEEE 1394a
1 x LAN(RJ45) port
6 x USB 2.0/1.1
8-Channel Audio I/O
1 x PS/2 Keyboard port (Purple)
Internal I/O Connectors 3 x USB connectors (6 ports)
1 x Floppy disk drive connector
1 x IDE connector
5 x SATA connectors
1 x IEEE 1394a connector
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
Chassis Intrusion connector
1 x COM connector
CD audio in
24-pin ATX Power connector
4-pin ATX 12V Power connector
System Panel (Q-Connector)
BIOS 8 Mb Flash ROM
AMI BIOS, PnP, DMI2.0, WfM2.0, SM BIOS 2.3, ACPI 2.0a, ASUS EZ Flash 2,
ASUS CrashFree BIOS 3
Manageability WOL by PME,WOR by PME,WOR
by Ring,Chasis Intrusion,PXE
Accessories 1 x UltraDMA 133/100/66
4 x SATA cables
1 x Q-Shield
1 x User’s manual
2 in 1 Q-connector (USB, System panel; Retail version only)
*The floppy disk drive cable is purchased separately.
Support Disc Drivers
Express Gate
Anti-virus software (OEM version)
ASUS Update
AMD OverDrive Utility (AOD)
Form Factor ATX Form Factor
12 inch x9.6 inch ( 30.5 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 with nothing serious out of place.
The floppy drive port is again, relegated to the very bottom of the board,
perhaps to dissuade its use altogether. The 4-pin ATX12V power connector
is in a poor spot as well, especially when you consider the increasing
popularity of cases with bottom-mounted power supplies. There are four
fan headers, but only the one next to the CPU socket has PWM support.


Three aluminum heatsinks, painted blue give the board a relaxed look.
The southbridge cooler is unimpressive and the fins on the northbridge
cooler are oddly oriented with some pointing upwards and others angled
to the side.


The board’s capacitors are all solid-state and a nice VRM heatsink is
present next to an orderly line of chokes.


The back panel is fully loaded with HDMI, eSATA, FireWire and S/PDIF goodness.
The only things missing are a PS/2 mouse port and WiFi.



For enthusiasts, the options available within 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.

“Ai Tweaker” menu with maximum values entered.

The Ai Tweaker menu is unintimidating with plenty of options.
Ample CPU, chipset and DRAM voltage and frequency settings are available and
with an unlocked CPU, the multiplier can be increased to an insane level.

“Hardware Monitor.”

The Hardware Monitor section displays three fan speeds, and
has three different settings for the CPU and Chassis fans: Silent, Optimal
and Performance.

BIOS Summary
CPU Frequency
200 to 600MHz
CPU Voltage
0.8000V to 1.7000V in 0.0125V increments
Memory Frequency
800MHz, 1067MHz, 1333MHz, 1600MHz (may depend on CPU)
Memory Timing Control
Memory Voltage
1.50V to 2.50V in 0.02V increments
Northbridge Voltage
1.30V (default) to 1.60V in 0.02V increments
Southbridge Voltage
1.20V (default) to 1.35V in 0.15V increments
Integrated Graphics
VGA Core Clock
150Mhz to 1500Mhz (500MHz default)
Memory Options
UMA, SidePort, UMA+SidePort
UMA Frame Buffer
32MB, 64MB, 128MB, 256MB, 512MB
SidePort Clock Speed
1066MHz, 1333MHz, 1400MHz to 1700MHz in 30MHz increments
SidePort Voltage
1.50V, 1.60V
Fan Control
Performance, Optimal, Silent
Chassis Q-Fan
Performance, Optimal, Silent

Overall, there’s plenty in the BIOS to satisfy almost everyone,
including those who wish to tinker with the onboard graphics.


Test Setup:

CPU-Z screenshot: Phenom II X3 720.

Measurement and Analysis Tools

Benchmark Test Details

  • Eset NOD32: In-depth virus scan of a folder containing 32 files of
    varying size with many of them being file RAR and ZIP archives.
  • WinRAR: Archive creation with a folder containing 68 files of varying
    size (less than 50MB).
  • iTunes: Conversion of an MP3 file to AAC.
  • TMPGEnc Xpress: Encoding a 1-minute long XVID AVI file to VC-1 (1280×720,
    30fps, 20mbps).

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

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.

We also performed a short series of benchmarks featuring real-world timed tests
and synthetics. Power consumption was monitored to determine overall energy

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 features a Phenom II X3 720 Black Edition with unlocked multiplier,
a Zerotherm Zen FZ120 CPU cooler with Nexus 120mm fan connected to a variable
DC fan controller so the fan’s power draw does not come into play. The rest
of the system consists of two sticks of Corsair Dominator DDR3 memory running
at 1333MHz (9-9-9-24) in dual channel, an Asus Blu-ray drive, a 5400RPM notebook
hard drive and an OEM Seasonic 400W power supply. 128MB of system memory was
assigned to the IGP in addition to the included SidePort memory.

Test Results
Test State
X3 720 BE @
2.8Ghz (C&Q)
X3 720 BE @
1.6Ghz (0.9125V)
System Power
System Power
Sleep (S3)
Rush Hour
Coral Reef
Drag Race
(Blu-ray H.264)
CPU Load
C&Q minimum state: 800MHz, 1.025V.

With a high speed triple core processor at stock settings, our regular IGP
video playback tests were easily handled by the M4A78T-E. Typically we use a
lower speed dual core processor to more easily gauge differences in CPU utilization,
but there are no dual core processors on the market for AM3 socket yet. Power
consumption was fairly good — on average we see idle and CPU load power consumption
of 40W and 90-95W respectively on an AM2+ motherboard with a 45W X2 processor.
The M4A78T-E with a 95W X3 720 increases power usage by only 15-20W.

The lowest CPU multiplier the BIOS would allow was 8x, resulting in a minimum
clock speed of 1.6GHz. We were able to get the CPU stable at this speed with
a core voltage of only 0.9125V, lower than the 1.025V the processor runs at
when idle using Cool ‘n’ Quiet (though C&Q reduces the CPU speed to 800MHz
when idle). This reduced power consumption when idle and during video playback
by 5-10W. CPU usage was comparable underclocked — an AM3 system is overkill
for media playback alone.

CPU-Z screenshot: Phenom II X3 720 idling with C&Q functioning.


CPU-Z screenshot: Phenom II X3 720 minimum underclock/undervolt.

AM3 vs. AM2+

The board chosen for comparison is the Asus
. Made by the same manufacturer and sharing the same chipset
and an almost identical feature-set, it comes closest to being the AM2+ version
of the M4A78T-E. Before testing, the M3A78-T was flashed to the latest BIOS
to ensure processor compatibility and Cool ‘n’ Quiet was confirmed functioning.

Test Results: AM3 vs. AM2+
Test State
M4A78T-E (AM3)
M3A78-T (AM2+)
System Power
System Power
Sleep (S3)
Rush Hour
Coral Reef
Drag Race
(Blu-ray H.264)
CPU Load

We expected to see little difference between the two platforms, but testing
showed a clear advantage for the AM3 board in terms of power consumption. We
saw improvements in the order of 10 to 22W during video playback and CPU/GPU
stress testing. If Asus’ boards are any indication, there seems to be an efficiency
penalty for using an AM3 processor on a AM2+ board.

Performance Differences

To determine whether there is any clear-cut performance difference between
the two boards, a short suite of synthetic and real-world benchmarks was run.

Benchmark Comparison: AM3 vs. AM2+
M4A78T-E (AM3)
M3A78-T (AM2+)
Power (AC)
Energy Used
Power (AC)
Energy Used
Memory set to AUTO in BIOS.
M3A78-T: 800MHz, 5-5-5-18.
M4A78T-E: 1333MHz, 9-9-9-24.

On paper, the only real difference between the systems is the memory.
The M3A78-T uses lower speed DDR2 with better latency while the M4A78T-E has
higher speed DDR3 with poorer latency. The frequencies/latencies selected by
the BIOS are what we would consider average for budget DDR2/DDR3 memory. Given
the frequency/latency tradeoff, it was no surprise to us that our real-world
tests split between the two boards, though the synthetics all favored AM3
by a small margin.

Power efficiency echoed our previous results — it was clearly superior on
the M4A78T-E. Even the two benchmarks the AM3 system lost, the energy used performing
the two tasks was less. It could be due a quirk in the M3A78-T or perhaps there is
something inherently different in regards to power regulation when it comes
to AM2+ vs. AM3 processors.

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 and monitored the fan speeds using SpeedFan/PC Probe.
A Xigmatek 92mm PWM fan (2800 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 Speed Behavior
Q-Fan Setting
Fan Speed
1540 to 2800 RPM
0 to 1610 RPM
450 to 1400 RPM
Trigger Temp.
/ Range
46°C / 14°C
Fan Speed
2190 to 2800 RPM
0 to 1610 RPM
500 to 1400 RPM
Trigger Temp.
/ Range
40°C / 14°C
Fan Speed
2800 RPM
960 to 1610 RPM
980 to 1400 RPM
Trigger Temp.
/ Range
35°C / 6°C

The Silent and Optimal Q-Fan settings were similar, activating at CPU temperatures
of 40°C and 46°C respectively, but having the same 14°C range before
the fan speeds topped out. The Optimal setting also had a lower minimum CPU
speed. The two Chassis fans seem to be tied to the same controller even though
the Scythe 80mm fan did not spin to start (it probably has a higher starting
voltage). If either of these two options are used, make sure to use fans with
low startup voltages.

The Performance setting had the CPU fan spinning at maximum speed right from
the beginning. The Chassis fans began to increase in speed when the CPU temperature
reached 35°C, and by the time it hit 41°C, they were both at their respective
top speeds as well.

If you decide to use the BIOS’ fan control and a decent third party heatsink,
we recommend using the Silent profile. We ourselves would connect the CPU fan to
one of the Chassis fan headers instead, because of the wider speed range offered. The controller for the CPU_FAN header
does not lower the speed low enough in our opinion.

SpeedFan Support

For Windows users, 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. Asus PC Probe on the right.

SpeedFan reported the two Chassis Fan speeds, but for some reason registered
only a one or two digit number for the CPU Fan speed. Temp1 matched the CPU
temperature read-out in Asus Probe, and Temp2 matched “MB” which,
through thermal testing we determined to be related to the temperature of the

SpeedFan allows for full control of the CPU and Chassis Fan headers. Speed01
controls the CPU fan using PWM, but cannot reduce the speed below 45% or so.
Luckily Speed02 varies the output voltage of the same header resulting in full
control. Speed03 controls both fans on the Chassis Fan headers. To enable fan
control, select the first chip in the Advanced tab of the Configuration menu
and set the three PWM modes to “Software Controlled.”


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. To test the board’s
cooling for the various chips on the PCB, we conducted a short thermal stress
test for 15 minutes, loading both the CPU and GPU while the CPU fan was reduced
to 6V. A spot thermometer was used to read the hottest point on various portions
of the board.

The southbridge heatsink and the chokes around the CPU socket registered fairly
cool at around 50°C, while the hottest point on the VRM heatsink was about
63°C. The northbridge heatsink, despite it’s size was the hottest of all
at 85°C. This is a bit higher than we are used to seeing but still acceptable
given the lack of top-down cooling from the CPU cooler and our open air testing
environment. It should run cooler inside a case with properly directed airflow.


With AM3 being so fresh, we had nothing to compare the Asus M4A78T-E to except
its AM2+ variant, the M3A78-T.
We found only minor differences between the two in terms with
the boards splitting real-world timed tests, and the AM3 M4A78T-E pulling slightly
ahead in synthetics. From a pure performance point of view, there is no compelling
reason to consider AM3 over AM2+.

More compelling is that AM2+ will soon be history, and future AMD CPU offerings will come in AM3. The improved power efficiency we found
on the AM3 board is also significant. The earlier AM2+ M3A78-T used more power during
all of our tests, varying from as little as an extra 2W idle and 5W during anti-virus
scanning, to as much as 20W during VC-1 playback and 26W when archiving files with WinRAR.
In long term use, the average difference should fall somewhere between those extremes. DDR3 memory
is supposed to use less energy, but that’s not enough to explain the differences we
found today. While all the current Phenom II AM3 processors are 95W parts, AM2+ Phenom II’s are 125W. Perhaps the 95W TDP applies only when the AM3 processors are used with AM3 boards? This is an issue that calls for a bit more digging, and we’ll report power results with other AM3 boards in the near future.

The Asus M4A78T-E board is solid, with plenty of features including eSATA and
CrossFireX, a tried and tested IGP with SidePort memory, fan control for up
to 3 fans, and a BIOS that is unintimidating to mainstream users yet satisfying
to enthusiasts. Stability was perfect and no oddities cropped up during testing.
The only thing negative we could say about the M4A78T-E applies to the AM3 platform
in general — the current lack of CPU choice and extra cost of DDR3 memory, but neither will stay static.

The potential of this new board will be better utilized when faster AM3 CPUs are released.
Still, if you already have an AMD CPU, it’s a good step upgrade. The price of DDR3 memory has already come down significantly. A 4GB kit of DDR3-1333
can now be acquired for only $20-$30 more than 4GB of DDR2-800. The M4A78T-E
itself is moderately priced at $140~150
, no more than its AM2+ counterpart, the
M3A78-T, and way lower than Intel i7 boards, so it is the first reasonably priced DDR3-based platform
that value-minded users can consider.

Our thanks to ASUSTeK
and AMD for the product samples.

* * *

Articles of Related Interest
AMD Phenom II processors for AM3

Phenom II:
AMD Pulls Closer

790GX Showdown: Gigabyte vs. MSI
Zotac GeForce 8200-ITX WiFi: A Compact
AM2 Solution

Asus P5N7A-VM: Geforce 9300

Asus P5Q-EM G45 mATX motherboard
Asus M3A78-T: AMD’s IGP Gets Another

* * *

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