Thermals and Power Consumption

The new MacBook Pros have the potential to draw more power than the previous generation. Despite being built on a 32nm process, the new 15 has twice the cores of last year's model—there's no question that it can draw more power under a full load.

I measured maximum power consumption at the wall using the same power brick and a fully charged battery. I chose two high-load scenarios: Cinebench 11.5 and Half Life 2. The former will fully load all CPU cores while the latter ramps up CPU and GPU usage.

Maximum Power Draw—Cinebench R11.5

Under Cinebench the new quad-core 15-inch MacBook Pro draws 70% more power at the wall than last year's dual-core model. This shouldn't be surprising as Cinebench scales nearly perfectly with core count—twice the cores should result in nearly twice the power draw. The scaling isn't perfect since we are dealing with different architectures and a number of factors such as display remain static. The new 13-inch MacBook Pro isn't as worrisome, it has 88% of the power usage of the high end 2010 15-inch MBP and 81% of the battery capacity.

Maximum Power Draw—Half Life 2: Episode 2

The Half Life 2 comparison is not quite as bad, although the new 15-inch MBP still uses 45% more power under full load compared to the previous generation. These numbers tell you one thing: although the new MBP is significantly faster than its predecessor, it can also draw significantly more power. Running the same workload the new MBP shouldn't have any problems lasting as long as the old MBP on battery, but running a more aggressive workload will result in shorter battery life as a result of the higher max power consumption. In other words if you use the higher performance to do more, you can expect your battery to last proportionally less than the 2010 MBP.


The 15-inch MBP uses an 85W power adapter (left) and the 13-inch MBP uses a 60W adapter (right)

Drawing more power also has another unfortunate side effect: the bottom of the chassis gets even hotter than before. I took some crude temperature measurements when I did the 2010 MacBook Pro reviews last year. I pointed an IR thermometer at the center of the bottom of the notebook, right where you'd have your lap, and measured surface temperature in a couple of scenarios.

Surface Temperature—Web Browsing

While browsing the web with tons of windows/tabs open I noticed a small but tangible increase in surface temperature of the 2011 15-inch MBP compared to the 2010 model. Even the new 13 is warmer than last year's 15. Under light workloads none of these temperatures are high enough to really be a problem.

Surface Temperature—Half Life 2: Episode 2

Load up the system however and you start getting into the uncomfortable zone. The new 15 breaks 38C, while the new 13 is actually only marginally warmer than the old 13 thanks to the use of Intel's HD Graphics 3000.

Max Temperature—Half Life 2 Episode 2

The biggest difference I noticed was the max temperature near the exhaust fan(s) on the notebooks. The new 15 is a whole 13C warmer than last year's model.

There's no way to get around it—if you're going to be using these systems to anywhere near their potential, they are going to get significantly warmer than last year's. Also, as a result, the new systems are noisier. Fans are more likely to spin up and given how small they are, they are quite audible. If this is a deal breaker for you, the best advice I can give you is to wait for Ivy Bridge.

Ivy Bridge will bring mild updates to the Sandy Bridge architecture, an increase in performance but more importantly it'll bring Intel's 22nm process. At 22nm I'd expect somewhat lower power usage than what we're seeing here today. Ivy Bridge is expected to ship in the first half of 2012, with updated MacBook Pros arriving ~2 months post introduction.

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  • claytontullos - Friday, March 11, 2011 - link

    The laptop was not constantly crashing, maybe 1-2 times per week. Had I sent it in to them nothing would have happened because they would have run their own woefully inadequate ram test. I replaced the ram and have not had any crashes since.

    HP also insisted that I reinstall vista when my led screen turned solid blue at a certain angle.
  • alent1234 - Friday, March 11, 2011 - link

    i've been dealing with computers long enough to remember lifetime warranties being standard and dell sending replacement parts with no questions asked.

    around 2000 is when it changed and i've had to lie to tech support even when i called for large customers with tens of thousands of dell computers bought.

    my own personal experience with HP tech support for a work laptop vowed me to never buy a HP laptop again unless it's from costco or dirt cheap to where i can buy one every year and junk it without thinking twice.

    same with dell. 7 years ago i bought a $1500 laptop with the 3 year warranty. 2 years into it i find out the battery is not covered. Unlike with Apple where the entire laptop is covered and going to the genius bar doesn't mean being on hold for hours and needing a translator to talk to someone
  • erple2 - Friday, March 11, 2011 - link

    Huh. I've never had a problem with HP service before. I've had HP laptops ranging from the 2800T to an Elitebook 6930p to an Envy 15. In each case, there was an issue that had to be resolved, and I received prompt, accurate service, including a box they sent to me to ship the device back to them. Yes, they didn't cross ship a laptop, but that's not practical.

    My experience with Apple's Genius Bar, however, hasn't been so rosy. Personally, I'd rather wait on hold in my house for 2 hours than wait around at a Genius Bar for 2 hours for someone to actually help you. Granted, it was crowded, but it's irrelevant to this discussion.
  • claytontullos - Saturday, March 12, 2011 - link

    When the problem and solution is crystal clear to even the most ignorant person then HP's service is fantastic: ie: Won't Power On, Disc wont eject, Nothing on screen.

    However with intermittent issues HP's support is horrible. Even speaking with a supervisor nets little reprieve from ignorance.
  • argosreality - Thursday, March 10, 2011 - link

    The Envy line comes with its own dedicated support group that is not the usual, outsourced to India group. Quite a bit better. Also, strangely I have seen memory pass the Pc-doctor tests (usually what HP uses outside of the BIOS runs) but fail memtest. Not sure why, could just be different test algorithems
  • starfalcon - Sunday, May 15, 2011 - link

    What kind of 13 inch laptops have discrete graphics anyway?
    Except maybe that smaller Alienware.
  • Taft12 - Thursday, March 10, 2011 - link

    <i>My preference would be two cables: one for power and one for peripherals/display. Today, it's five.</i>

    What you've just said is that Macbooks need a Dell Latitude-style docking station option in the worst possible way. Your preference is 2 cables. Mine is zero. Just snap in. (I've had this for over a decade now)

    If Apple is serious about phasing out desktops as you suspect, that'll be something that needs to come first.
  • secretmanofagent - Thursday, March 10, 2011 - link

    I've always been hesitant of docking stations. I've had a Dell that for the most part would undock somewhat correctly, and currently have an HP work computer that refuses to undock at all. For me, the convenience has always been hampered by the usability.
  • gstrickler - Thursday, March 10, 2011 - link

    Actually, with MagSafe power and Thunderbolt, that's essentially possible. A dock that includes a connection to both ports could offer Mini-DisplayPort, DVI, VGA, USB, Ethernet, FireWire, eSATA, and Thunderbolt connections, and optionally, even a PCI slot or two. With 4x PCIe compatibility and 20Gb/s bidirectional throughput, a Thunderbolt port has plenty of bandwidth for that. Of course, Apple is currently the only company who could offer it with the MagSafe connection, but a third party could at least reduce it to 2 quick connections.
  • erple2 - Friday, March 11, 2011 - link

    Huh. My windows laptop has only 1 connection that handles mouse, keyboard, monitor, power, ethernet and external storage. 'Course that's the beauty and convenience of a (working) docking station, something that I never really thought was worthwhile until I actually got one.

    I'm bummed that consumer products don't come with one.

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