This article is not going to discuss the differences between x86 and PPC hardware, instead we are going to take a look at reasons why you might want to choose one platform over another for your linux application. The following articles provide detailed information on the hardware differences between x86 and PPC, and are well worth a look.

RISC vs. CISC: The Post-RISC Era
G4 vs. K7: an architectural comparison
The Pentium 4 and the G4e: an Architectural Comparison

Cost
The first major difference between PPC and x86 hardware platforms is the cost involved. Apple provide lower cost PPC offerings, while $799 is not bad at all for an iMac, and the iBook at $1299 is definately a first choice if you are in the market for a laptop, as far as a non-portal system is concerned, x86 is definately the cheaper option. You can throw together a 850MHz+ system for less than half the price of the bottom of the line iMac, if you just need a server or a beat-up box, then x86 is the way to go, if want to avoid high costs. If cost is not a factor, and you want to experiment with the PowerPC platform, then the Apple hardware is definately a cost-effective way to enter the platform.

Quality and Performance
One of the reasons to go with PowerPC hardware over slightly lower cost x86 hardware is quality. Apple and IBM both tend to provide higher quality equipment than some x86 component vendors, again it is still possible to put together a good x86 system with quality parts for about the same price as PPC hardware, if not less.

So that leaves performance, and despite what marketing folks would like you to believe, comparing both is like comparing apples and oranges, however, Linux does provide us with a common platform on which we can try to benchmark both hardware platforms. You can't compare a 1GHz G4 with a 1GHz Athlon or P4, because of the hardware design. Different CPUs perform well at different tasks. PowerPC tends to perform better with different tasks than x86, PowerPC handles floating point operations a lot better, again, that depends on the x86 processor you are comparing it to.

Bottom Line
If you want a laptop for development, web design, college work, office work etc, then Linux on an iBook is the way to go. The iBook offers firewire, usb, ethernet, modem and is a nice light-weight laptop. If you just want a generic server, then save your money and look at a Duron or Athlon system, and spend more money on disk capacity and memory than an all-in-one solution like an iMac or a fancy G4. On the other hand, if you are doing heavy floating point applications, rendering, compiling or complex math operations, the G4 offers some advantages over its x86 counterparts. The best thing to do, is to look at what you need to do, your budget and whether or not you want to experiment with a new platform, read the hardware articles at the start of this feature and make an informed decision based on your requirements.