X-bit labs

IBM PowerPC G5: Another World

Category: CPU

by Victor Kartunov

[ 01/27/2004 | 11:36 AM ]

We decided to discuss a slightly unusual but very interesting topic: Mac computers. Today we would like to offer you a detailed analysis of the processor architecture for the newest Mac systems – IBM PowerPC G5. It is not just the first desktop processor with 64bit architecture, but a really interesting solution with a lot of unique technologies and features from IBM. Read more about it now!

Table of contents:

• Starting Out
  
• Part 1: The Computer, in a System-Shell
  
• Part 2: 64 Bits of Your Desktop
  
• Part 3: Introducing the PowerPC970
  
• Part 4: PowerPC970 as a Fortune-Teller
  
• Part 5: Instruction Set and Registers
  
• Part 6: Execution Units
  
• Part 7: More Bus Bandwidth
  
• Part 8: Performance, from the Marketing Point of View
  
• Epilogue
  
• Links
  

Starting Out

While the proponents of processors from Intel and AMD meet in a head-on crash and peruse the lines of the specifications for fresh arguments, other manufacturers manage to sell computing machines of quite another kind and quite different technical characteristics. So there is a natural question – what kind of machines they are? Are they better or worse than those we usually use? Do they have any unique features? Why people buy Apple Macintosh computers at all (hereafter referred to as Macs)?

So, this is one of the first times in our history that we, at X-Bit Labs, put aside the glorious PC to take a look at the Mac, or, to be more precise, at the microprocessor used in the Mac. I think this article should be strongly recommended to any person who heard to the prophets of the Mac faith (yeah, they are not far from religious zealots sometimes). Some of them say that Macs are just absolutely different, and others claim the Mac to have an unbelievably fast architecture – the competitors would take a decade just to catch up with it.

However, I haven’t seen yet a Mac in the list of fastest processors, according to SPEC CPU 2000. It means the microprocessors used in Macs don’t run that fast as far as raw performance is concerned. So, where do these rumors about a “fundamentally different architecture” come from? Why is there an opinion that Macs suit best for industries like the printing industry? Do Apple’s advertising claims about the leadership in graphics processing have any ground at all?

There was also one more reason for my decision to write this article. We don’t often stop and take a look around; we don’t readily see what other things, besides the x86 architecture in all its variations, the computer industry has developed for us. I think it is exciting to take a closer look at microprocessors that are now a “parallel world” rather than competitors to the x86 models. The Mac is another world, not a direct competitor in any way.

Over a year ago, the new processor for the Mac was announced, the PowerPC970. After initial agitation subsided, we now have an opportunity of telling whether the release was successful. Was it a breakthrough Apple is known to make with every next release of the Mac, or maybe the new Mac just keeps on the tradition of its predecessors?