AOpen i915Ga-PLF with Power Master

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WITH AN INTEL 660

The new 600 series are equipped with several features that, in combination, are new for Intel desktop processors.

  • EM64T - Extended Memory 64-bit Technology is Intel's term for the 64-bit extensions developed by AMD for the x86 architecture. Athlon 64s have had this technology for two years.
  • Execute Disable Bit - First introduced in the AMD A64, this technology denotes certain areas of main memory as "non-executable" and prevents some basic security threats on properly configured systems. Windows XP SP2 is required for support of this feature.
  • 2MB L2 Cache - A move up from from 1 MB of L2 cache to 2 MB of L2 cache to improve overall system performance.
  • Enhanced Intel SpeedStep Technology (EIST) - Intel's desktop version of the feature on their moblie processors, which they've used for some years: It slows down CPU clock speed, by lowering the front side bus, the multiplier and voltage when the processor is idle. It reduces heat and power consumption at idle, like the AMD Athlon64's Cool 'n' Quiet, but does nothing to change the power demand at full load.

The last item listed, EIST, is what we're most interested in here. As with Cool 'n' Quiet in the Athlon 64, there are a number of requirements for EIST to work. The following is summarized from Intel's How-To Document about EIST.

Desktop System Requirements

To take advantaged of Enhanced Intel SpeedStep® technology, certain requirements must be met

  • CPU: An Intel® Pentium® 4 processor 6xx sequence.
  • Chipset: A motherboard with one of the following chipsets: Intel® 910 or Intel® 915x/925X/XE Express Chipsets.
  • Motherboard: The motherboard must support dynamic VID. All Intel® desktop boards support dynamic VID.
  • BIOS: A BIOS must have support for Enhanced Intel SpeedStep technology.
  • Operating System: Current supporting OSs include:, Microsoft Windows* XP SP2 includes native support for Enhanced Intel SpeedStep® technology. Linux* support is also available. (Public Kernal: 2.6.9, 2.6.10; Red Hat*: EL4 or higher; SUSE*: SLES-9 SP1).
  • Software/Drivers: No specific software or driver updates are currently required. However, it is recommended that you always have the latest drivers for you system hardware.

Integration

Standard integration procedures should be followed for installing all the various system hardware components. Once all the hardware components have been installed correctly (or if the system is already functional) take the following recommended steps:

  1. Download and run the latest BIOS update for you motherboard. Check with your motherboard manufacture to ensure their latest BIOS contains support for Enhanced Intel SpeedStep technology
  2. Ensure Enhanced Intel SpeedStep technology is enabled in your BIOS. For Intel desktop boards the Intel SpeedStep technology option is under the, “Power,” tab and labeled, “EIST.” Ensure it is set to, “Enabled.”
  3. Ensure your OS has support for Enhanced Intel SpeedStep technology. For Windows XP operating systems, install SP2 if you haven’t already done so.
  4. Finally Enhanced Intel SpeedStep technology must be turned on in the OS. Currently, for Windows XP SP2 operating systems Enhanced Intel SpeedStep technology by default is off. To turn it on do the following:
    • Under Control Panel – open Power Options
    • Under the Power Schemes pull down menu
    • To turn Enhanced Intel SpeedStep technology ON select, “Minimal Power Management,” power scheme.

NOTE: The default minimum clock speed in EIST for all 600 series processors at this time is 2.8 GHz or 200 MHz FSB x 14.

My checklist for EIST:

  • An Intel 660 processor test sample was on hand. This was not a retail product.
  • BIOS update R1.01 for the AOpen i915Ga-PLF promised "Added EIST support." The motherboard was already running on this BIOS.
  • Windows XP SP2 was fully updated and running on the test system
  • All the items listed by Intel under Integration were followed.

AOpen i915Ga-PLF does fully support enable EIST with BIOS R1.01. With the Intel 660 installed, the boot screen flashes a message stating "C1E BIOS SUPPORT" — which means that dynamic CPU voltage management is engaged. This is one of the functions of EIST. There are no menu items anywhere in the BIOS that turns EIST on or off. If you install an EIST-featured CPU, the support appears to be automatically turned on.

Would there be any problems in running Power Master and EIST together? My instinct was to say no, because Power Master only changes the front side bus between 140 MHz, 200 MHz and 210 MHz, while EIST changes Vcore and the CPU multiplier.

A full set of data for Power Master settings were collected with the Intel 660 processor.

POWER MASTER w/ INTEL 660 CPU SUMMARY
CPU Load
EIST*
Power Master**
CPU Speed
AC Power
CPU Voltage
CPU Multiplier
FSB
Power Master set to NORMAL
idle
1.18
14
200 MHz
2.80 GHz
67W
max
1.35
18
200 MHz
3.60 GHz
162W
Power Master set to PERFORMANCE
idle
1.18
14
200 MHz
2.80 GHz
67W
max
1.35
18
210 MHz
3.79 GHz
168W
Power Master set to AUTOMATIC
idle
1.18
14
140 MHz
1.96 GHz
62W
max
1.35
18
210 MHz
3.79 GHz
168W
Power Master set to SILENT
idle
1.18
14
140 MHz
1.96 GHz
62W
max
1.35
18
200 MHz
3.80 GHz
162W

* The CPU Voltage and Multiplier are both always set by the EIST utility built into the CPU (and supported by the AOpen motherboard.
** The FSB is controlled by the Power Master feature in the motherboard.

The Intel 660s AC power for idle with Power Master turned off (Normal) is marginally lower than the 520 at idle with Power Master turned on. The relative effects of Power Master and EIST render the settings for the two processors identical except for the Vcore. The combination of EIST and Power Master together are more effective at reducing power consummation that either alone. Some salient comparisons:

Processor / state
CPU Voltage
CPU Multiplier
FSB
CPU Speed
AC Power
520 at idle, Power Master ON
1.38
14
200 MHz
2.80 GHz
67W
660 at idle Power Master OFF
1.18
14
200 MHz
2.80 GHz
67W
660 at idle w/ Power Master ON
1.18
14
140 MHz
1.96 GHz
62W

NO FAN CONTROL OPTIONS w/POWER MASTER

Acoustically, the only potential problem with both the Silent and Automatic modes is that the SilentBIOS fan control defaults to Smart Control with the trigger speed set to 55°C. There are no other options if Power Master is engaged.

While many users might think this is perfectly reasonable, there is a sonic advantage to letting the CPU hit a higher temperature before having the fan ramp up in speed. With the highly sensitive PWM speed controlled fan on the stock Intel cooler, the Smart Control setting at 55°C makes for frequent and annoying changes in fan speed. A better heatsink fan can solve the problem, however.

A Zalman 7700Alcu modified with a Nexus 120mm fan was pressed into service. Despite this being a 3-wire fan rather than the 4-wire fan used on the Intel, it connected perfectly fine on the motherboard header. The fan worked well with the SilentBIOS set Smart Control, ramping up and down between 500 and 1000 RPM with nary any audible noise.

UNDERVOLTED & POWER MASTERED?

An obvious question comes to mind: Can the CPU core voltage (Vcore) be reduced manually while Power Master is engaged?

Savvy PC silencers know that most processors can easily take a 0.1V reduction in Vcore without any penalty of instability. This small drop in voltage can lead to a drop of several degrees in CPU temperature. It is difficult to calculate what the power drop might be when the CPU is in idle, but at full load, a 0.1V drop in Vcore from 1.4V to 1.3V would lead to the Intel 520 TDP falling from 84W down to 72.4W. At idle and at the reduced 1.96 GHz clock speed, the power reduction will be no more than a few watts, but this could still make total AC power drop down to the mid-high 50W range for our test system, which is nothing to scoff at.

The answer to the question is: It depends on which CPU.

Non-EIST: The full range of AOpen's Vcore adjustments (in 0.025V increments down to well below 1V) is accessible with the the Intel 520 regardeless of Power Master setting; logic would suggest this probably applies to any non-EIST processor.

EIST: With the 660 processor, changing the CPU core voltage is not an option in the BIOS at all, regardless of the Power Master setting; logic would suggest this probably applies to any EIST processor.

CONCLUSIONS

The AOpen i915Ga-PLF stands out from the crowd by virtue of Power Master. Yes, it has a nice BIOS, it does have SilentBIOS and Silent TEK, it is full-featured and stable without being costly... but the real attraction of this board is Power Master.

We hope dynamic Vcore adjustments will find their way into Power Master as it develops and evolves, along with a broader range of user controls. We also hope this feature will be integrated into more than just the three motherboards that have it now. It may also be just a question of time before Intel adopts a similar technology for their own boards, especially if they plan to continue selling non-EIST processors.

Regular SPCR visitors will recognize that this board and the Intel 660 are perfect to try with CrystalCPUID which we posted an article about few days ago. We will tackle this topic, but in a separate article a little later in the future.

Aside from the obvious for silent PC builders, there are other significant benefits of Power Master, most of which relate to cooler operation and reduced power consumption. The latter should be a concern for everyone in our age, but it may be especially significant for corporate buyers seeking to equip an entire office or branch or building.

Kudos to AOpen for Power Master.

Much thanks to AOpen for providing us the i915Ga-PLF sample, to Intel for the 660 Test Sample, and to Newegg.com for the Intel 520 CPU loaner.

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