G3 vs. G4

[neesley]

I currently have a 400 MHz G3 and am looking to upgrade to a faster laptop.

Could anyone explain the difference between the 900 MHz G3 in the iBooks and the 867 MHz G4 in the lower end Powerbooks?

Also I don't understand the concept of the different levels of cache - L2, L3 etc. Could you explain this to me as well and also how this affects performance?

Thanks

 

[MacsRgr8]

Simple answer:

Main difference between G3 and G4: G4 = G3 + Altivec unit. When an application is "altivec enhanced", it will run alot quicker on the G4 than on the G3.
Level 1 cache = memory direct on chip.
Level 2 cache = very fast memory, close to processor, for very speedy access.
Level 3 cache = very fast memory, usually on motherboard, for quite speedy access.
A processor will "lookup" an instruction in this order: L1, L2, L3, RAM.
So simplified, having more L2 cache, and even L3 cache will speed up the total performance of the processor.

This is a very simplified answer, and ofcourse it's only generally speaking.
Hope it's clear.

The AluBook 867 will outperform the iBook 900 easily.

 

[Catfish_Man]

Originally posted by MacsRgr8
Simple answer:

Main difference between G3 and G4: G4 = G3 + Altivec unit. When an application is "altivec enhanced", it will run alot quicker on the G4 than on the G3.
Level 1 cache = memory direct on chip.
Level 2 cache = very fast memory, close to processor, for very speedy access.
Level 3 cache = very fast memory, usually on motherboard, for quite speedy access.
A processor will "lookup" an instruction in this order: L1, L2, L3, RAM.
So simplified, having more L2 cache, and even L3 cache will speed up the total performance of the processor.

This is a very simplified answer, and ofcourse it's only generally speaking.
Hope it's clear.

The AluBook 867 will outperform the iBook 900 easily.

Good answer, but I'd like to add that the main reason the PB will outperform the iBook (on non-altivec heavy tasks) is the faster hard drive, system bus, and ram. The processor itself is pretty similar in speed. Hard drives become a pretty major factor for laptops, on desktops they're usually fast enough that other things limit you more.

 

[MacsRgr8]

Indeed.
Tnx for adding that.

 

[MrMacMan]

The G3 owns the G4 is everthing was the same, like bus speeds and hard drive, etc.

The G4 has Altevec but without that the G3 would own it.

 

[cb911]

if you just want a faster laptop, then you should consider the 900MHz iBook. they represent very good value (for a Mac) and will probably feel a little bit more 'snappy' when Panther is released.

if you've been using a 400MHz G3, then i'm guessing that you haven't been using Photoshop or similar apps. that's another way of seperating the G3 & G4's. G3 = e-mail, general use, internet etc. G4 - definitely consider if you use Photoshop or similar apps.

you can also check out sites like www.barefeats.com. they've got comparisons of the 900 iBooks vs. the 867 AlBook. the iBook does beat the PB in some operations. having a look at those tests should show you which one would be suitable for you.