[Ti] New 15" 1.25 GHz PowerBook

[Jeremy Kezer]

JG,

>There is no need for L3 cache anymore.  L3 cache was only there to help
>compensate for the low bus bandwidth.  The L3 ran at 133Mhz.  Now the Bus
>bottleneck is gone.  To Put 133Mhz L3 cache in there would BECOME the new
>bottleneck in an outwise DDR speed memory pipeline.  This is why P4 etc has
>no L3.

Huh? This is incorrect.  L3 cache is attached DIRECTLY on its own bus 
to the processor, which runs at a multiple of the processor's clock. 
The old 17" PowerBook had 1MB of L3 cache running at 250MHz and a 
system bus at 167MHz.  It had 256k L2 cache running at 1GHz.

I think the performance increase in the old vs new 17" is due to the 
larger L2 cache (which runs at the processor's clock rate, 1.33GHz).

Jeremy

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jeremy at kezer.net                              http://www.kezer.net/
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