Working on client software means that it's easier to justify getting a new toy tool to work from home with. Since the Mac Pros have just been revised, I took this opportunity to upgrade from my mid-2006 model to a more recent one. After jumping through some hoops, I finally have it all set up, and out of curiosity I compared the time it took to do a clean WebKit build times against the old machine (and my work setup):

Apple actually uses WebKit compilation time as a benchmark on their own page, so it certainly does show off the many cores of the machine. Not all build steps are perfectly parallelizable though, so the CPU usage meter isn't quite as redlined all the time as the above screenshot would indicate.