OS X is a 64 bit OS which will run on the G5 Processor, also 64 bit, from IBM. It will also run on the G3 and G4 processors but not as 64 bit. Next year it should also be running on some form of Intel chip, probably still with the 64 bit capability.
Hardware has basically become a non-issue between the two platforms. Mac's use the same drives, memory and monitors as a PC and now that one of the major Video card makers has 'fessed up and stated that video cards for the Mac are the same as video cards for the PC, just different drivers, we can look forward to better, cheaper versions of them too.
PCI & PCI-X are also supported.
The only problem you will have is on the gaming side. There are a considerable number of games for the Mac, a lot of the PC games have Mac versions, and with the move to Intel processors and the ease of producing a cross platform program, we will probably see simultaneous releases of the major games for both platforms.
The really serious gamer should probably be using one of the console systems as their machine of choice.
P
Mac has OS X now and I am under the impression that this is a 64 bit operating systems that run off of IBM 64 bit chips? Besides that what is different with macs compared to windows/linux pcs hardware wise. Also is there enough software out there for gamers?

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