I'll add a little input here as well, if you can understand what I say, congrats to you
x86 processors, which what non-Apple computers are, are barely comparable to Apple computers. This is mostly due to their architecture. Apple computers are targeted toward people that require more power, such as image editors, 3d modellers(Think Pixar, who has the 2nd most powerful computers in the world, 2nd to the US government), and the like. As I said, they have more power. With that power, they also can perform more functions per clock cycle. Since they can perform more functions per clock cycle, they don't need as fast of speeds, so their speed, measured in hertz, khz, mhz, or ghz now, doesn't have to be so high, however, like everyone else, they're trying to push those numbers higher and higher, hoping to get more sales.
x86 processors, which are most Intels and AMD's(I say most because I'm not sure about their server processors, like Xeon) run at much higher rates. x86 processors run at much higher speeds because they cannot perform as many functions per cycle as Apple/Motorola's processors. Since they run at higher clock cycles, they also have faster responses for playing video games. But because of their architecture, even x86 processors aren't the same. Intel's processors run at higher speeds, but they lose more functions than AMD processors, which means their processors must re-submit the same functions over again, which slows down the overall performance of the processor. But Intel has designed a new feature called Hyperthreading, which is supposed to help with this problem, and is supposed to help out greatly with programs such as Photoshop. What they don't tell you is that it's still nowhere near as good as what Motorola's later processors do.
AMD runs at slightly slower speeds than Intel's Pentium processors, but AMD processors excell at many more things than Intel's processors do because it can perform more functions per cycle. From speed tests, AMD processors handle office suites, internet browsing, and the such better and faster than Intel's processors. But since it runs slower, it lags behind in games such as the games based on the Unreal engines.
With most PC's, there is also more room for expansion, with PCI slots and drive bays(the areas where the CD-ROM drives and Hard Drives are), whereas with most Apples(e and iMac's) everything is pretty much as compact as it can get, unless they want to make the computers laptops. The only expansion for those is with firewire(which is nearly as fast as USB2, but it is much older), or with the upcoming FireWire2, which runs at 800MB/s(which is faster than what processors can spit data through). The only apples that truely have expansion capabilites are the Powermac G4's(which are the only Mac's I would take). Their main problem is that they are very expensive if you want a better one, such as follows:
Dual 1.42GHz PowerPC G4
2MB L3 cache/processor
2.0GB DDR333 SDRAM
120GB Ultra ATA/100
SuperDrive
ATI Radeon 9700 Pro
128MB DDR video memory
FireWire 800
56K internal modem
Bluetooth Included
which runs for $3,799.00 US.
Here's the page for the Powermac G4's:
http://store.apple.com/1-800-MY-APP...kFyw5zKSB9vy0y/0.0.5.1.0.5.21.1.2.1.2.0.0.1.0
I'm not sure how well your english is, especially when talking about computers, but I hope you understood most of what I wrote.