AOpen i915Ga-PLF with Power Master

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Here is the obligatory big picture for those who like to pore over the visual details. Click on the image below for a 1024 pixel width image.


The AOpen i915Ga-PLF is not too big, and there's no little whiny fan on the northbridge chip.

About the only thing that is a bit awkward on this board is the position of the 24/20 pin ATX connector. It's close to the PCIe graphic card slot, well past the CPU socket. It is positioned far away from the AUX 12V (2x12V) connector, and the wires have to reach over and around the CPU heatsink/fan. A position closer to the "top" edge of the board would have made for greater convenience and simpler cable management. However, the near-central position of the ATX connector may have to do with optimizing current paths on the board, particularly to the PCIe slot, which calls for up to 75W to be delivered via the ATX cable.


The ATX connector is positioned almost in the center of the board.

Before we start digging into the feature that really fascinates us about the i915Ga-PLF, let's sum up several weeks of working with the board:

  • It is a nice package of features without being completely over the top.
  • The price is nice.
  • The BIOS Vcore and FSB adjustments (both up and down!) were close to the most flexible and enthusiast-friendly I've seen. This is fairly typical of ATX AOpen boards.
  • The absence of a fan on the modest size NB heatsink may limit overclocking options.
  • The board always remained perfectly stable throughout the testing and in general use.

OK, that's done, now let's move on to the burning question.

WHAT IS POWER MASTER?

So let's get back to the heart of the matter: AOpen describes Power Master this way:

Power Master is a hardware controller to detect your CPU actual loading. And give your system the real time performance. When the loading is really low, it can lower the CPU current and make the fan slower to provide you the quietest working environment. On the contrary, Power Master will increase the CPU current and overclock in time to provide you the best performance.

If you didn't understand that, too bad, because that's all there is from AOpen. There are no other explanations. Not in the manual, PDF brochure or elsewhere at the AOpen web site. It took many careful readings of the above paragraph, several hours of hands-on trial-and-error, and a phone chat with Sunny Wang, a customer service engineer at AOpen America, to fully understand what Power Master is about. Much of its functionality is, in fact, described by the above. It's just not very clearly done. Let's take each line one at a time.

1) Power Master is a hardware controller to detect your CPU actual loading. This tells us that the load on the processor is monitored.

2) And give your system the real time performance. Something to do with changing performance dynamically based on CPU load.

3) When the loading is really low, it can lower the CPU current and make the fan slower to provide you the quietest working environment. So the CPU power consumption is reduced when it is idling and the CPU cooling fan speed is also reduced.

4) On the contrary, Power Master will increase the CPU current and overclock in time to provide you the best performance. The phrase "on the contrary" is used to mean "on the other hand". The CPU current and clock speed is increased when needed to provide the best performance.

This line-by-line breakdown still does not tell the complete story, and it's lacking in many of the fine details. Let's see if I can sum it up for you:

A Functional Summary of AOpen's Power Master

Power Master is a dynamic, real-time, CPU clock speed adjustment utility built into the motherboard and controlled within the BIOS menu. It provides Cool 'n' Quiet type functionality for any socket-T processor that can be installed on this motherboard; it does not require any support to be built into the processor. It also ties CPU thermal monitoring along with CPU load monitoring with automatic fan speed adjustments for the CPU heatsink fan via the 4-pin PWM voltage output header. Despite AOpen's description, the CPU core voltage is not changed, only its clock speed, via the front side bus.

In essence, Power Master is a simplified Cool 'n' Quiet built into the motherboard, independent of the CPU! As some of you are aware, dynamic idle throttling has finally come to Intel's latest 600 series desktop processors, but exactly how this is implemented has not been examined in detail this far as far as I know. This also does nothing for all the other Prescott processors, which continue running hot either at idle or at load. AOpen's motherboard-embedded feature can help all Prescott-core socket 775 Intel processors achieve considerably lower idle power.

Power Master can do nothing to stop the processors from running at their default power when there is a high work load. Prescott core P4s will continue to run hotter than the older Northwoods or the comparable AMD Athlon 64 processors. However, consider this data cited by the U.S. Environmental Protection Agency: Typical office computers sit idle 90~98% of the time that they are turned on. This means that reducing idle heat / power is highly significant for improved thermals and acoustics as well as for reduced energy consumption.

TEST SYSTEM

The following components were used to assemble an open-bench test system with the AOpen i915Ga-PLF motherboard. It was as lean and minimalist a system as we could make.

  • Intel 520 processor -- P4-2.8 Prescott, 1Mb cache, 800 MHz FSB in 775 casing). Spec'd by Intel for a Thermal Design Power of 84W (and a calculated Maximum Power of 100W), and a maximum casing temperature of 67°C. Loan from Newegg.com
  • Intel 660 processor -- P4-3.6 Prescott, 2Mb cache, 800 MHz FSB in 775 casing. The 660 is EM64T enabled (for 64-bit compatibility like the A64s), and features Enhanced SpeedStep (like Cool 'n' Quiet). Spec'd by Intel for a Thermal Design Power of 115W (and a calculated Maximum Power of 141W), and a maximum casing temperature of 67°C.
  • Stock Intel HSF
  • Zalman 7700AlCu - modified with Nexus 120 fan
  • Samsung SM-352B Combo Drive (CD-RW + DVD-ROM)
  • OCZ DDR400 512MB DDR Platinum SDRAM Memory (single stick)
  • Seagate Barracuda IV 40G - One of our original quiet reference drives.
  • Antec Phantom 500 power supply (pre-production sample) - This is a high efficiency PSU; the results of our testing would certainly vary with the PSU.
  • Microsoft Windows XP Pro SP2
  • On-board integrated graphics card (IGMA 900)

Tools

  • AOpen Power Master monitoring software
  • CPUBurn stress Program
  • Seasonic Power Angel AC power meter
  • CPU-Z
  • SpeedFan


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