Re: [LUG] Laptops

[Rick Timmis <rick@xxxxxxxxxxxx>]

Yep Simon is right on the button with this one.

The judgement criteria between apple and pc, has to come back to 
processor achitecture. As simon states the Imac uses a RISC processor or 
Reduced Instruction Set. Intel provide CISC or Complex Instruction Set 
Chips. To take this back away makes it a simpler analogy. At the early 
dawn of Microprocessors was the 8080 which is the early evoultion of 
8086 through 80386 and onto Pentium chips.
Apple began with the 6502 I believe, Later moving into Motorola 68000 
and then on upwards. I am a little unsure whether Apple still use 
Motorola chips, but the RISC processor is still king to Apple.

Here's an example of performance.

in the early days a Zilog Z80A was running at 4.0MHz
Comparing this up against Motorola's 6809E which ran at about 0.8MHZ

When one looks at this today we say the Z80A must be 4 times better at 
performing than the 6809.
Not so each instruction the Z80 processed would take anywhere between 20 
and 40 Clock cycles. 4.0MHZ = 4 Million cycles per second
The 6809 averaged between 1 and 4 Cycles per instruction, it averaged 
about 1/8 of the processor time to execute it's instructions.

So now we say Oh then the 6809 is twice as fast as the Z80, Again not 
so, the Z80 was a CISC chip, as a result it could achieve more from a 
single instruction than the 6809. Which left the 6809 processing more 
instructions to get the job done.

The reality of the situation was that there wasn't really much in it.

If all things where equal and Intel didn't have the bigger marketing 
budget, then the Apple would more than likely be King, At the end of the 
Day the GUI was an Idea Steve Jobs from Apple came up with, and BG took 
the idea to the Market.

Bottom line my money would be on the Imac.

Ramble over
Rick

Simon Waters wrote:

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> Nick Kew wrote:
>  
>
> > > But when I see 800MHz my heart sinks.
> > >      
>
> ..SNIP..
>
>  
>
> > I certainly wouldn't let 800MHz worry you.
> >    
>
> When the G4 cubes arrived it provided similar floating point
> maths capabilities as a single Cray processor from 1991 or there
> abouts, but without the need to have the builders in to build
> you a cooling system the size of your garage.
>
> (Actually Cray later made an M series box with LOADS of memory
> and similar processors about the same size as an office
> photocopier, with no fancy cooling required. Perfect for big
> finite modelling problems).
>
> In their "busting the megahertz myth" Apple noted that on
> photoshop benchmarks the G4 733MHz processor outperformed a
> 1.7GHz Pentium 4 by 33%. Now no doubt Apple took a favourable
> benchmark result of those available, but it makes the point.
>
> Megahertz is not a meaningful comparion of computing performance
> except perhaps between different version of the same processor.
>
> An 800MHz Itanium is twice as fast at integer maths as an 800MHz
> Pentium III. Which reflects the trend in design, sure pushing up
> the Megahertzs is a cheap performance boost if you can
> manufacture the faster processors reliably. But historically it
> has been more successful in a technical sense to produce
> processors that do more each clock cycle in the simplest fashion
> possible.
>
> This was the whole RISC debate, and why SUN use to beat Intel,
> why Intel has to steal technology from Digital's Alpha
> processors, and why Intel co-operated to get processor know-how
> from HP.
>
> In a business sense the most successful processors were Intel's,
> which is just another case of the best technology not winning
> (except in the end Intel adopted most of it to stay competitive,
> one way or another).
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