(Here’s another guest post by Pat Moorhead, Vice President of Advanced Marketing at AMD. Pat’s postings are his own opinions and may not represent AMD’s positions, strategies, or opinions. You can find Pat at Twitter as @PatrickMoorhead.)

The current defacto standard used by PC makers to measure notebook battery life is MobileMark 2007 (MMO7). This piece takes a look at the basic facts behind the notebook brightness settings recommended by MM07, comparing that to some typical home electronics devices and the average settings some consumers are using for their notebook displays.

The facts about MM07 and notebook display brightness

MM07 requires the following: “The display brightness should be measured for a white screen while on battery and be set at the lowest possible setting, no lower than 60 nits.”

So what is a nit?  Wikipedia defines a nit as a “candela per square meter.” Think of a “nit” as a unit of measure of brightness.

How does 60 nits compare to brightness of other home electronics?

To see what 60 nits relates to in real-world usage, we tested some typical home electronics devices  without changing any settings, other than shutting off “auto adjustment” on the phones.

Here are the test results:

Device	White Screen	Nits (cd/m2)	MM07	“X” MM07
BlackBerry Bold	Memopad	338	60	5.63
BlackBerry Storm	Memopad	326	60	5.43
iPod 80GB	Menu	311	60	5.18
Archos 7	Background	260	60	4.33
Optiquest Q9	Notepad	235	60	3.92
iPod Touch 32GB	Flashlight	225	60	3.75
Viewsonic VA912b	Notepad	188	60	3.13
T-Mobile G1	Flashlight	181	60	3.02
NEC Multisync 1700V	Notepad	173	60	2.88
Dell XPSOne	Notepad	155	60	2.58

The lowest nit measurement observed was at least two and a half times brighter than the MM07 brightness level of 60 nits on which notebook battery life is measured.

To see how nits relate to notebook screen brightness, we tested a few notebook PCs to see what the “max nits” measured when the screen was set to the highest setting.

As you can see from the figures below, the MM07 requirement was between 20-30 percent of the sample notebooks’ maximum screen brightness.

	Max Nits	MM07	MM07 %	“X” MM07
Mac Air Gen 1	310	60	19.4%	5.17
MSI X340	214	60	28.0%	3.57
HP dv2	195	60	30.8%	3.25

What notebook display brightness setting do consumers use?

These results were interesting enough to prompt an informal poll of Twitter and Facebook users asking about the display brightness setting on which they place their notebooks. The responses are both qualitative and quantitative,.

Quantitative: Neowin actually placed a poll on their community website asking the question, “What brightness level do you run your notebook?”  More than 1,100 community members voted in a few days, and according to Shane Pitman, Editor-in-Chief, “Polls require a member account, and to be logged in to said account. Provides accountability, keeps people from voting multiple times.”

The results were overwhelming in that 75 percent of the Neowin community member respondents kept their notebook display brightness between 61 and 100 percent.

Qualitative: These responses were as valuable as the quantitative as they gave insight into why they did this.  Some comments gave insight into the folks who use their notebooks at very low display settings.

The following question was posed on Twitter  “Research question: what display brightness do you run your notebook at? (Please RT)”.  Here is just a sampling of public tweet responses.

• “On the machines I see, normally I prefer to have them fully backlit with the slider up to around 75% or so.”
• “I run my laptop at maximum brightness unless the battery is really low, or I have an external screen. “
• “Now running MBP 15.4″ 3.1 at 75% brightness with auto adjust turned ; but was at 100% without auto adjust til you asked! “
• “90 – 100% brightness, 90% of the time. “
• “depends entirely on my battery level and surroundings. “
• “Research question: what display brightness do you run your notebook at? (Please RT). I run full bright 95+% of the time. “
• “oh sorry :), 100% unless I’m running low on battery, where I bring it down to a minimum, I’m guessing 50%, but thats rare“
• “usually around 60-70%“
• “i don’t use them much, mainly desktop, but i either have brightness at full or minimum: latter at night and if battery low“
• “When running laptop on battery, i set brightness to 25-40%, when plugged in -100%.“
• “100% brightness. Left default setting (and I appreciate it that way… old eyes). “
• “slammed up to full when possible, monitor screens vary though“
• “mine is usually as bright as I can make it. I hate dim screens. “
• “max brightness notwithstanding battery impact. “
• “I lower my screen brightness to the lowest, usable level that’s comfortable. It’s all about the battery life. 😉 “
• “Agreed…I think mine is usually around 30% or so. “
• “it varies by location due to lighting levels. Usually around 30% or 40%. Never > 50% when on battery. “
• “ME: 90 to 100% on AC, about 50 % on battery when I’m watching movies and about 20 to work. “

We also received some really interesting responses related to interpretation, explanations, tools and resources on brightness after asking about “60 nits”.

• “not all that hard. Need 800+ nits to read screens in direct sun, 30-150 for night highway signs: http://bit.ly/cjxJB“
• “60 nits = table in an office with 300 lux illumination: http://bit.ly/FvoKe BTW sRGB calibration target = 80 nits. “
• “oh and here’s a Kodak guide on how to use a digital camera and gray card as an ad-hoc nit estimator: http://bit.ly/1IMLK3“

The Bottom Line:

• The MM07 test requires a 60 nit or higher display brightness. To maximize battery life benchmarks, systems are set at the minimum allowable 60 nit level. This setting is thereby integrated into this battery life benchmark that is then used in notebook PC advertising to consumers.
• Worst case, the display brightness of many home electronics is 2.58 times more than the MM07 nit setting requirement.  Based on the small set of notebooks tested, MM07’s 60 nits equated to around 20-30 percent of the maximum notebook brightness.
• Unscientific querying on Twitter and Facebook says many classes of users crank their screen beyond 61 percent, and many at maximum brightness.  Some self-selected a lower brightness setting to conserve battery life.

Does MM07 use realistic notebook brightness setting in its battery life tests that consumers make buying decisions from?  You be the judge.   Whether you agree or disagree, what are your thoughts? And here’s a quick poll:

 
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