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Discussion Starter · #1 ·
Just when I thought that the 12" PB was the shoe in with me, I'm having reservations (yep, Heart).

Just gave the specs a good scan, and the L2 cache size is an underwhelming 256k (on chip or not??). I was a little bummed to say the least, knowing that the Tis are @ 1MB. :( Yes, I know that I should be more than happy with my Pismo as it wields a powerful MB as well. Now, to add a twist, I just noticed that the Ti 550 had 256K as well :eek: ?!?! what was that all about? Esp when I know the iBooks are hitting you with 512K. So my question is this, how much attention should I give this cache quandary? I do know what I need it for, but if the Ti 550 ran off the same 256, I'm sure that this 12" PB should run well as well, no? Are they offering the 256K due to the fact that they are giving us this PC2100 (what is the speed on those anyhow?) Ram? Why so many varying specs.... Damn you Apple! Factual comments welcomed. ;)
 

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All of the G4 (Motorola) powerbooks have 256k of Level 2 cache. You seem to be confusing Level 2 (on chip) with Level 3 cache, which is a little different and can go up to 2MB on some G4 systems.

The iBook uses a different chip (G3 IBM) with a larger on-chip cache of 512k Level 2.

Basically this just represents the choices made when designing the chip; my guess is Motorola decided the 256 is enough when the velocity engine can handle some processing tasks.

Cache memory is really dependant on the chip's design and shouldn't be viewed alone. It's just one factor affecting performance.

Also, this is very expensive memory (added on-die). Apple could have included the additional 1 or 2 MB of Level 3 but it would have added hundreds to the price. For example, only the megabuck 1.25G DP desktop has processors with the 2MB Level 3 specification.
 

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Compared to my desktop, it has a faster IDE controller, faster bus speed and faster memory throughput, versus the absence of L3 cache with the same 867 processor. I would expect those differences to add up to very snappy performance on the portable.
 

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Discussion Starter · #5 ·
i sure hope so. Is there some kind of rule of thumb that I should know so that I can some how compute a total?? What specs should I be looking at 1st - in order of importance??
 

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Discussion Starter · #6 ·
So with that said, I should be fine with the 256? I wanna be.
 
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