To get an idea of the actual impact, I performed three tests: First, I just let the laptop sit there, do nothing and let it drain its battery to get an idea of the absolute maximum battery life. Then, I used the laptop to browse the web and multitask with several Office programs and PhotoShop. I repeated all those steps both under Windows 7 and OS X Lion. For my last test, I simply played a 1080p movie in loop until the battery died.
So how did my 17" MacBook Pro fare? Not well:
Windows 7 stood no chance against OS X. Instead of the usual 4.5 hours (idle) and 4 hours (typical workload), I got 3.5 and 3 respectively. During HD playback, my MacBook Pro gave up after a bit over 2.5 hours running Windows, while Lion kept on playing for roughly 3.5 hours.The story didn't change much when I switched over to a loaner 2011 MacBook Air (Core i7), although the difference isn't as noticeable.
The verdict? Windows 7's power management is pretty awesome on Windows laptops -- not so on Macs. The built-in Boot Camp drivers (even using 4.0) tend not to conserve as much energy as they should. Plus, the CPU and GPU fans keep on spinning constantly, even under low workload, and the device produces an enormous amount of heat. Using OS X, the MacBooks tend to stay a bit cooler and quieter under the same conditions. However, it never reaches dangerous levels and even the fan noise isn't as bad as you might think. I think this is the major downside of running Windows on a Mac and that's the reason I needed to shell out that extra cash for a HyperMac 150Wh, which gives me an additional 10-12 hours of battery life.
Performance: A Win for Windows?
With the sloppiness of Boot Camp driver quality fresh in my mind, I feared for the performance of Windows. I put both OSes through the paces on my mid-2009 MacBook Pro with an Intel Penryn C2D (3 GHz), 4 GB of RAM and a 256 GB Toshiba SSD and here's what I found:
First, you have to understand, that comparing performance of Windows and Mac OS X isn't quite as easy as it sounds. Only a few selected benchmarks are available on both sides of the fence: I can't really compare PCMark points with the Geekbench score. However, by using a combination of basic tasks and synthetic benchmarks, I was able to draw a clear picture on the performance differences.
Here's the set of benchmarks I performed, plus the results. To get a good measure, I made it my rule to perform all tests three times and average the numbers:
Start-up time: Mac OS X wins, but only by a small fraction
I use my trusty stopwatch to determine the exact time it takes from selecting the boot drive (see screenshot below) to when the desktop is visible.
While that doesn't mean that all background services and startup programs are fully loaded, it still gives an indication as to how fast the OS initializes drivers and is ready to use. The results?
It's not as bad as I thought: Lion has some known slow boot issues, which makes it come closer to Windows -- before I upgraded to Lion, Snow Leopard booted in about 15 seconds and would have beaten Windows 7 hands down. Plus, the moment you select the Windows partition, all Macs seem to go back to a DOS-like shell (there's even a blinking white cursor on the top left corner) for about 5 seconds and just waste time.