Re: memory bandwith on Powermacs
Tested myself...
benh wrote:
>> Reasons might be many and various: memory bandwidth being _much_
>> lower on all but the latest Apple machines, compared to equivalent
>> i386 boxes, being one of them. RISC vs. CISC code generation might be
>> another, also that is pure speculation on my part. Different levels
>> of compiler omptimisation might be another.
> Note that all recent Apple machines (the "core99" series) have a very
> much higher memory bandwidth (100Mhz on a 64 bits wide bus and better
> memory controller) than any previous model.
> Also, the page copy optimisations Paulus added to 2.4 seem to give
> full benefit on G4 CPUs (better cache management than G3s ?) to reach
> about 200Mb/sec on a G4/350 with the hdparm buffer cache test.
Same for me on the TiBook/400; between 200 and 220 MB/s
And yes, the 2.4 kernel is a _big_, even _huge_ improvement: no less
than _double_ the memory bandwidth, according to the hdparm buffer
test.
Cheers
Michel
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