Selecting Processor, Memory, and Hard Drives
For a server, the amount of RAM that a Mac can hold is almost as important as the processors in it. Select your Mac model for the RAM it holds as well as for the processor. The more expensive Macs hold significantly more RAM than the lower-end models.
With hard drives, you can always replace the hard drive or, in some Mac models, add hard drives.
Selecting processors for your Mac servers
With Apple hardware, you can't choose just any processor the way you can with PCs. To get a particular type of processor, you have to select the Mac model. Within each model are some differences in clock speed. Mac Pro offers the most options in processors at purchase time, giving you a choice of one or two multicore processors.
Processors with multiple cores act as multiple processors. So two dual-core processors are equivalent to one quad-core processor. This is why processing power is sometimes described in terms of the number of cores rather than the number of processors.
You don't need a brand-new Mac for Lion Server. An older Mac is perfectly fine — as long as it has a 64-bit Intel processor. Lion won't run on the older PowerPC processors. Sometimes, the Mac's model name gives it away: A Power Mac has a PowerPC processor. All Mac Pro and MacBook models use Intel processors. Mac minis, iMacs, and Xserves, however, came in both PowerPC and Intel processor versions. When in doubt, check the About This Mac window (see Figure 2-1), accessible from the ...