February 14th, 2008
MacBook Air Diary-Day 15: Temperature benchmarks
A big concern for anyone using a notebook computer for any length of time is the heat it generates. It actually came to a head a few years ago when the lawyers at most notebook computer manufacturers replaced the term “laptop” with “notebook” for fear of litigation.
Apple recommends that their notebook computers only be used on a flat, stable surface – not on your lap. They go so far as saying the following on their MacBook care Web site and in the user guide:
When you’re using your MacBook or charging the battery, it’s normal for the bottom of the case to get warm. For prolonged use, place your MacBook on a flat, stable surface. Do not place your MacBook on your lap or other body surface for extended periods of time. Prolonged body contact can cause discomfort and potentially a burn. The bottom of the MacBook case functions as a cooling surface that transfers heat from inside the computer to the cooler air outside. The bottom of the case is raised slightly to allow airflow, which keeps the unit within normal operating temperatures. In addition, warm air is vented from the slots in the back of the case.
(emphasis mine)
To measure the heat generated by the MacBook Air I created 12 temperature zones on the bottom plate. I flipped over the MBA and mapped locations in three rows and four columns. Zones 1 to 4 are across the top from left to right. Zones 5 to 8 are in the middle row and 9 to 12 are the bottom row.
I measured the temperatures (in degree Fahrenheit) on the bottom of an MBA (1.6GHz HDD) and MBP (2.4GHz Santa Rosa) after approximately three and five hours of use using a Mastercool 52224 infrared thermometer. Both machines were attached to AC power and sitting on a cloth upholstered ottoman.
Take the jump to compare the MBA to the MBP temperatures after three and five hours of use.
(The tables below are based on the temperature zones in the image above.)
|
91 |
95 |
102 |
104 |
|
91 |
94 |
96 |
99 |
|
90 |
91 |
93 |
95 |
|
90 |
95 |
101 |
100 |
|
89 |
92 |
96 |
95 |
|
87 |
88 |
91 |
92 |
Table 2: After five hours of use, the average temperature on the bottom of the MBA actually dropped to 93 degrees Fahrenheit with the hottest area (101 degrees F) being in zone three. The drop in temperature is most like the effect of the internal fans kicking in.Then I compared the temperatures of the MBA to a MacBook Pro (C2D Santa Rosa, 2.4GHz) in the same circumstances (connected to AC, sitting on an ottoman). Temperatures were measured in the same 12 zones as the MBA.
|
102 |
104 |
107 |
107 |
|
102 |
108 |
106 |
102 |
|
101 |
103 |
100 |
98 |
Table 3: MacBook Pro C2D Santa Rosa temperatures after three hours, average temperature is 103 degrees with the hottest area (108 degrees) being in the middle left, over the CPU.
|
107 |
109 |
111 |
110 |
|
106 |
112 |
106 |
98 |
|
104 |
107 |
99 |
97 |
Table 4: MacBook Pro C2D Santa Rosa temperatures after five hours, average temperature is 106 degrees with the hottest area (112 degrees) being in the middle left, over the CPU.Although these tests aren’t scientific and an upholstered ottoman is not an ideal setting for a notebook computer to sit on, they still tell a story. Under similar circumstances, the MBA consistently runs about 10 degrees cooler than the MBP.In my experience using a lap stand is highly recommended when using any notebook computer for more than an hour one your lap. Using a stand dropped temperatures, on average, another 10 degrees from the temperatures listed above. A post on some of the laptop stands on the market will follow in another installment.
What do you do to keep your lap cool when using a MacBook?
