Latitude E6400 Owner's Lounge

also, disable vista aero, and set color to 16 bit, and set refresh rate to 40hz. also, if you dont need them, you can set a script to disable devices, or manually do it in the dev manager. (cd drive especially)

 

so its beneficial to disable the cd drive if you dont use it often?

 

yep, there is (at least in my setup) a noticable improvement to battery life, although i have not done scientific testing to this regard, so if anyone disagrees, let me know.

 

From DCP Panel of your laptop, under Power Manager, there is a button that opens a new panel where you can disable power devices, such as the optical drive, Smart Card reader, firewire, and more...
I suggest that root, as my experience disabling my contactless Smart Card reader from Device Manager did not cut the power for it. it just disabled Windows from detecting it/using it/loading the drivers.. not actually cut the power. I have to test again with BIOS.. as this was with BIOS A09

 

so yes through DCP, but no through device manager?

 

Read it. Unfortunately, it is not dated.

Here is what that article tells me...

Sound Power vs. Sound Pressure

Sound can be measured by i) acoustic sound power or by ii) acoustic sound pressure, using a logarithmic decibel (dB) scale (10 dB = 1 bel). Drive measurements/specifications use acoustic sound power.

How Loud is Loud?

0 dB is the threshold of human hearing. 120–130 dB is the most a typical person can tolerate. Sound pressure measures the pressure level of noise recorded by the ear. Sound power measures the average total amount of acoustic energy coming from an object.

The smallest change a typical person can detect is 3 dB sound pressure, or 1.5 dB sound power. An increase of 6 dB is a doubling of measured sound pressure, although it takes an increase of 10 dB sound pressure to sound twice as loud to a person. An increase of just over 3 dB sound power is a measured doubling, though it takes an increase of 5 dB sound power to sound twice as loud to a person.

Some typical ambient noise levels (sound pressure) are:
20–30 dB for a quiet library or whisper.
40 dB for the average home.
60 dB for a normal conversation.
90 dB for a commercial truck or a train.
120+ dB for a jet airplane or rocket taking off.

Sound power measurements are significantly higher than sound pressure measurements, so the typical ambient noise levels listed above would have LARGER SOUND POWER numbers.

Drive Sound Power

A Seagate drive family acoustic sound power spec is worst-case... some builds may be more quiet. If a drive is noiser, then it is either out-of-spec and/or amplified by ambient conditions like chassis mounting.

Fanless/Very Quiet = mid-20 dB sound power range (seek is typically idle + 2 dB)

Seagate 2.5" Momentus 7200.3 7200RPM Laptop HDD = 2.3/2.5 bel idle/seek = 23/25 dB idle/seek

WD 2.5" Velociraptor 10,000RPM Desktop HDD = 29/34 dB idle/seek

My E6400 Momentus 7200.3 HDD is as noted above... fanless/very quiet. My desktop Velociraptor is as noted above... just a touch less quiet.

OEMs of consumer devices like laptops understand that drive mounting is critical to managing drive acoustics, yet Dell provides no drive mount isolation in the E-Series. Perhaps this is because new drives are so quiet that this provision is not needed?

The following Seagate quote may explain why some drives are just noisey... and perhaps more so at higher RPM:

"Motors rotate on bearings. These bearings may contain metal alloy balls, ceramic balls, fluid or other materials. For many years, disc drives have relied primarily on metal alloy ball bearings; they are cost effective, reliable, durable and reasonably quiet. They can, however, become louder over time if the motor sustains knocks and bumps that could cause minor damage to the motor bearings. Such damage might not affect the drive's performance, but it could cause the drive to become noisier. Also, the balls are never perfectly round (at a microscopic level), so there is always some amount of noise and vibration associated with metal ball bearings. Ceramic balls are more costly, but they are more perfectly round and less subject to the type of damage that could result in louder drives (they can't be dented)."

Conclusion

A 7200RPM HDD in spec is fanless/very quiet. If otherwise, then it's not in spec and is probably made worse by the E6400's direct chassis mounting.

Point remains, a higher RPM and/or higher capacity HDD is not necessarily a noiser and/or more power consuming HDD than a 5400RPM HDD.

Above quoted or adapted from: Seagate Disc Drive Acoustics.

GK

 

Well, I posted that link to show you that within a family, the number of platters can affect the acoustics. You did not seem to believe that.

For power consumption data, you can read reviews or charts like this one that compares notebook drives:

http://www.tomshardware.com/charts/2.5-hard-drive-charts/Idle-Power-Consumption,681.html

and:

http://www.tomshardware.com/charts/2.5-hard-drive-charts/Maximum-Power-Consumption,684.html

You can draw your conclusions about whether 7200 rpm drives run at higher power or not. But also think about this. All things being equal, the higher transfer rate of the 7200 rpm drives consume more power; this is a fact of life for CMOS circuits. The higher speed of the motors also requires more power.

An excellent site for low noise PC's is silentPCreview.com. They have a chart of recommended 2.5" drives for low-noise here:

http://www.silentpcreview.com/article29-page2.html

Of the 8 drives recommended, only one of them, the Hitachi single-platter 7K100, is a 7200 rpm drive. And even on that one, they said:

"Unfortunately, the high rotation speed causes a lot of vibration, which resonates at the relatively high (and audible) pitch of 120 Hz. A good compromise between notebook noise and desktop performance, but not quite as quiet as the best notebook drives."

Of course, you may have been very lucky and get a very quiet 7200 rpm drive. But as a group, the 5400 rpm drives are quieter. It would be best if you can find another E6400 with the slower drive to do the comparison yourself.

 

chances are VERY VERY good that all DCP is doing is disabling it the same way. GB and I have been debating that, and neither of us is really sure (disabling the smart card reader). Anecdotally, I think that disabling it through dev manager does help

 

>>Well, I posted that link to show you that within a family, the number of platters can affect the acoustics. You did not seem to believe that.

That is reasonable. And the article explained that Seagate specs are a drive family's worse-case, so they could be for the multi-platter builds. Still, worse-case sound power in those specs comes in fanless/very quiet, not 'sounds like a second fan'.

As for power consumption, looking at the Seagate Momentus specs for 5400RPM and 7200RPM drive families, you can not simply conclude that the faster drives consume more power.

Thanks for the links.

GK

 

Hi,
I have just bought an E6400!
do you have any recommendation and suggestion for me?

and a question?
how can I add a Bluetooth module device to my laptop? how much does it costs?