First Look: Cool down: Core 2 Duo switch drops MacBook temps

The MacBook’s switch to a Core 2 Duo processor may have produced only modest gains when compared to a similar upgrade to the MacBook Pro. But the updated MacBooks do beat their high-powered counterparts in one significant area—they run significantly cooler.

Testing by Macworld Lab found that the move from a Core Duo chip to a next-generation Core 2 Duo processor decreased the MacBook’s external temperature by about 5 degrees, allowing you to actually set this laptop upon your lap. The chip swap produced similar results for the new line of MacBook Pros released in late October, but potential buyers may be more impressed by the new MacBooks’ consistent peak temperatures of approximately 95 degrees Fahrenheit near the battery.

What we found

Using the same methodology we employed in our MacBook Pro temperature tests, we used the surface probe of an infrared thermometer to measure each of the Core 2 Duo-powered MacBooks in two “hot spots”—the bar above the F-keys and the area surrounding the battery. The black 13-inch 2GHz MacBook peaked at 95 degrees in the area near the battery and 100.7 degrees above the keyboard. The white 2GHz MacBook got a little hotter, with high temperatures of 95.4 and 101.5 degrees, respectively. Despite its slower clock speed, the 13-inch 1.83GHz MacBook was only slightly cooler at 94.4 and 100.1 degrees.

Compared to the Core Duo MacBooks these models replace, the results show a significant improvement. The 2GHz MacBook Core Duo heated up to 101.8 and 105.1 degrees during our last test—hotter than all three Core 2 Duo-powered models.

As with our last test, we measured internal temperatures of the Core 2 Duo MacBooks using the free application CoreDuoTemp. Results for the black and white 2GHz MacBooks were identical to those of the Core Duo generation with high temperatures of 167 degrees. The white 1.83GHz MacBook, however, peaked at 163 degrees.

MacBook Core 2 Duo Temperatures

Model Room Temperature External Temperature Near Battery External Temperature Above Keyboard Internal temperature
13-inch MacBook Core 2 Duo/1.83GHz 73.8° 94.4° 100.1° 163°
13-inch MacBook Core 2 Duo/2GHz (white) 73.8° 95.4° 101.5° 167°
13-inch MacBook Core 2 Duo/2GHz (black) 73.1° 95.0° 100.7° 167°
13-inch MacBook Core Duo/2GHz (black) 74.3° 101.8° 105.1° 167°
15-inch MacBook Pro Core 2 Duo/2.16GHz 73.5° 109.8° 110.3° 174°
15-inch MacBook Pro Core 2 Duo/2.33GHz 73.5° 116.1° 116.9° 174°
15-inch MacBook Pro Core Duo/2GHz 74.5° 115.3° 117.4° 176°
15-inch PowerBook G4/1.67GHz 74.1° 112.3° 112.5° N/A
<Cooler <Cooler <Cooler

Reference systems in italics .

All results are in Fahrenheit. Click here for results in Celsius. To measure external temperatures, we used an infrared thermometer to get readings on the bar above the F-keys and the area surrounding the battery on each laptop. Temperatures were measured while converting MP3 files in iTunes. Internal temperatures were recorded using the CoreDuoTemp application; because the program does not run on PowerPC-based Macs, we could not use CoreDuoTemp to record the internal temperature of the PowerBook G4.—MACWORLD LAB TESTING BY BRIAN CHEN

Here’s another indicator about the not-as-hot performance of the new MacBook models: the laptop’s user manual indicates that it’s cool enough to be used on your lap—at least for a while. According to Apple’s manual:

The bottom of your MacBook may become very warm during normal use. If your MacBook is on your lap and gets uncomfortably warm, remove it from your lap and place it on a stable work surface.

The warnings in the user manual for the Core Duo-based MacBook provide a stark contrast.

Do not leave the MacBook in contact with your lap or any surface of your body for extended periods. Prolonged contact with your body could cause discomfort and potentially a burn.

If 95 degrees still isn’t cool enough for you—and make no mistake, these machines still feel warm—programmer Magnus Lundholm recently released CoolBook, an application that reduces heat, fan noise and battery consumption by allowing MacBook or MacBook Pro users to modify frequency and voltage of their laptops. We hope to run future temperature tests that include this app.

[ Brian Chen is an assistant editor for Macworld .]

Editor’s Note: This story was reposted at 12:49 p.m. PT on November 27, 2006 to correct a reference to the MacBook Core Duo’s user manual.

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