Asus M3A78 Pro: An ATX 780G Motherboard

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TEST RESULTS

Our test system is fairly basic, featuring an ODM 80Plus power supply, notebook hard drive and Blu-ray drive. The CPU is a X2 4850e, a mid-level dual core 45W processor. It is cooled by a stock AMD heatpipe cooler with PWM fan connected to a variable DC fan controller (so the fan's power draw does not come into play).

vs. Gigabyte GA-MA78GM-S2H

Posted in the table below are the test results for the Asus M3A78 Pro board compared to the earlier 780G Gigabyte board we reviewed some months ago with exactly the same system components.

Test Results: 780G vs. 780G
Test State
Asus M3A78 Pro
Gigabyte GA-MA78GM-S2H
Mean CPU Use
Peak CPU Use
System Power
Mean CPU Use
Peak CPU Use
System Power
Off
N/A
2W
N/A
8W
Sleep (S3)
N/A
3W
N/A
9W
Idle
1%
2%
39W
1%
2%
38W
Rush Hour
6%
12%
64W
2%
8%
~53W
Coral Reef
42%
57%
65W
28%
39%
~65W
Flight Sim.
71%
85%
69W
47%
68%
~69W
Drag Race
73%
90%
69W
N/A
CPUBurn
100%
82W
100%
101W
CPUBurn + ATITool
100%
94W
100%
109W

The power consumption at idle was similar to the Gigabyte GA-MA78GM-S2H despite the fact that CPU-Z reported the CPU voltage to be approximately 1.00V — a full 0.10V less than normal. Strangely when we set the Cool-n-Quiet speed/voltage manually to 1.0Ghz/1.00V, the system only drew only 33W when idle, so either CPU-Z was wrong, or something was preventing CnQ from fulfilling its full potential. We ran into another quirk during playback of the Rush Hour H.264 clip — once it began playing, CnQ became disabled, forcing the CPU to run at 2.5Ghz when normally it would stay underclocked for such a light task, which saw CPU load peaks of just 12%. Afterwards, Vista's CPU power management settings had to be reset to default to re-enable Cool-N-Quiet.

The rest of the video playback was pretty much on par except for CPU usage, which was significantly higher on the Asus board, but this did not make its power consumption higher than the Gigabyte. The M3A78 turned out to be much more efficient at heavy load — measuring 15-21W lower than the MA78GM. It is difficult to account for these differences as many factors could be at play. Since we last tested the MA78GM, Vista Service Pack 1 came out, as well as several sets of ATI drivers, all of which could give the Asus an unfair advantage. To complicate matters, our MA78GM board was a very early sample, not a retail model and a bad BIOS flash bricked the board, which meant we were unable to retest it. And of course Asus is a completely different manufacturer, and the M3A78 has a slightly different feature-set and form factor.

vs. Asus M3N78 Pro

Asus M3A78 Pro vs. M3N78 Pro @ 2.5Ghz
Test State
Asus M3A78 Pro
Asus M3N78 Pro
Mean CPU Use
System Power
Mean CPU Use
System Power
Off
N/A
2W
N/A
2W
Sleep (S3)
N/A
3W
N/A
4W
Idle
1%
39W
1%
37W
Rush Hour
6%
64W
7%
~44W
Coral Reef
42%
65W
32%
~53W
Flight Sim.
71%
69W
48%
~67W
Drag Race
73%
69W
58%
~65W
CPUBurn
100%
82W
100%
93W
CPUBurn + ATITool
100%
94W
100%
102W

Compared head to head against the Asus nVidia-based equivalent M3N78 Pro, the results were surprising. When idle and playing video, the M3N78 Pro had an advantage in terms of power efficiency, especially when playing back less demanding clips. CPU usage was also significantly lower, making it a better choice for multitasking. Once heavy load was applied however, the M3A78 Pro pulled ahead dramatically, drawing 10W less power. From these results one could deduce that nVidia's IGP is actually more efficient, but the power regulation is not as good at high load, resulting in high power consumption when the CPU is pushed to its limit.

Test Results: Asus M3A78 Pro vs. M3N78 Pro @ 1.5Ghz
Test State
Asus M3A78 Pro
Asus M3N78 Pro
Mean CPU Use
Peak CPU Use
System Power
Mean CPU Use
Peak CPU Use
System Power
Idle
1%
2%
34W
1%
2%
43W
Rush Hour
8%
13%
40W
9%
12%
~47W
Coral Reef
52%
64%
46W
41%
50%
~47W
Flight Sim.
87%
96%
50W
73%
92%
~50W
Drag Race
87%
98%
50W
78%
88%
~50W
CPUBurn
100%
54W
100%
54W
CPUBurn + ATITool
100%
64W
100%
62W
X2 4850e @ 1.5Ghz undervolted to 1.100V, Cool-N-Quiet disabled

When the CPU speed was dropped to 1.5Ghz, our test setup could no longer play the two most challenging VC1 clips in our test suite. Accompanied by high CPU usage, the audio in the Flight Simulator video began to clip, and skipping was evident during the Drag Race clip. The M3N78 Pro had no problems with our test suite at 1.5Ghz. Underclocked, the M3N78 Pro was much closer to the M3A78 Pro's load power consumption, indicating once again that the M3N78 is "greener" at lighter load.



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