HD APM settings in Centrino Hardware Control?

I've got a Dell Inspiron 9300 with a Toshiba MK6026GAX drive. The machine is running Windows XP Pro SP2.

I downloaded and ran Centrino Hardware Control and noticed that it has the options to change the Acoustic and APM settings of the hard drive. I determined that it automatically changes the APM setting to 128 when the program is first run. The other settings don't change (I tested this by manually changing them and then deleting the settings file).

My question is what exactly does the APM setting do? The FAQ says it sets the power level for the hard drive. It defaults to minimal power without spining the drive down. Does this mean my drive will always run in low power mode now? Is this setting permanently stored in Windows or on the drive (like the acoustic setting) or is it only applied when CHC is run?

Basically I want to know what my original APM setting was before I ran CHC.

 

well lets see i also have centrino hardware control installed. i leave it on all the time cuz i think it actually makes my battery life a little longer. my hd setting right now is on default for the acoustic management and the apm is on 128 without spin down.

 

I ran some benchmarks to see what my HD speeds would be with different acoustic management and apm settings and I found absolutely no difference. I'm not sure what that means exactly. I also didn't think my HD sounded any quieter with acoustics set to quiet as opposed to performance, but since it didn't seem to do anything and my laptop shipped in quiet mode I left it like that.
I also noticed my laptop didn't spin down regardless of how the APM setting was set, but that could be because the disk never seems to be idle.

My main issue is that by having the APM set to 128 does that mean the drive will always run in low power mode even when it is being used? Also if the drive never spins down, will that prevent the system from going into standby mode when not in use?

 

hmm...good questions. i'm not really too sure about the acoustics adn the apm settings. all i did was put it on default. mine doesnt seem to do anything like what you said. so i have no idea if it will be using low power or high power. so you said that when you put no matter what the acoustic setting and apm the benchmark was the same? if somebody have some opinion on this i also would like to know.

 

The APM is a setting to allow your HDD to reduce power after booting/spinning up. I guess almost like how your CPU will run at full speed during boot and then drop to something slower save power. I believe it's the same method for the HDD. A HDD consumes a lot more power during the spinup then it does when it's idle. I guess disabling the APM wil lmake the HDD run at full power all the time. This might decease overall wait times when a read or write request is made to the drive (no need to jump power back up).

The Acoustics setting is an option to reduce the HDD's heads speed when reading/writing. This will reduce overall vibrations and therefore reduce noise. But it will generally reduce overall drive read/write speeds. When running a diag, I believe it bypasses these settings since it's just a test, that's why you don't notice any performance difference.

-Vb-

 

What I'm curious about is does CHC only override the default settings when it is running or does it make the change permanently. Since it seems to change the APM to not spin down, though it says it is low power without spin down which I'm not sure what exactly that means.

Basically I want to know if I remove CHC will my HD's APM settings go back to what they were before or not. I know the acoustics setting is permanent, but I'm not sure about the APM setting since I think Windows controls that somehow.

 

Morac,

I'm not sure how CHC works, but if it accesses the drives firmware directly, then it should be permanent (until you change it). Below is a User Guide for Hitachi/IBM's Feature Tool and it also explains exactly what each feature does and how it works.

http://www.hitachigst.com/hdd/support/ftool_user_guide_198.pdf

From what it says in the above PDF, your settings will stay the same (whatever you set with CHC) after you remove the program. Also, the PDF says the settings will stay after Power ON & Hardware/Software resets.

-Vb-

 

Hmm I wonder if my drive actually support these features since it is made by Toshiba. Though another program I ran seemed to indicate it does. Also from what I've read each manufacturer may implement APM slightly differently. For example for Toshiba, 80 is normal idle speeds with Standby while the CHC documentation lists 80 as minimal power mode without standby.

I'm also curious as to why this wouldn't affect benchmark programs since the implementation seems to be at the hard drive firmware level which any benchmark program must go through. Are there any real world test I can use to see if CHC's settings have impacted my system?

 

Morac,

Yes, I believe each manufacturer may set the values differently, so it depends on the brand you have. It's possible the Toshiba drive doesn't have a value of 128, that's why you may not have noticed a performance difference.

It's possible when running diagnostics, the HDD knows that it's just a performance test (since the benchmark programs don't actually write to the drives), it will bypass theses settings to show actual performance. (Just guessing)

It's also possible the CHC settings are completely ineffective and don't actually make any changes to the drives firmware.

I have not seen any real-world test results with these options enabled. I don't know if anybody has actually tried.

-Vb-