Re: poor relative G4 performance iBook/PowerBook
Hi,
Brian Morris wrote:
% time cat <huge_file >huge_file_copy
Install smartctl to check drive health
I also have a PowerBook 1ghz which is quite a bit faster than my
1.5ghz tho could be because the former has a bit more ram and a newer
hard drive and the latter has a defective 2nd ram slot
I wanted to investigate this further - except smartctl, I did more
extensive checks with file copying which are interesting, also, now that
keyboard works again, I investigated better what dmesg says.
Here some results:
dd if=/dev/zero of=output.dat bs=1M count=128
PB: 158 MB/s
iBook: 117 MB/s
dd if=/dev/zero of=output.dat bs=1M count=256
PB: 9.4 28.5 MB/s
iBook: 4.8s 56 MB/s
Copy of 256MB file
PB: 5.18 s
iBook: 2.7 s
This means that for 128MB there is some "cache effect" and there the
PowerBook beats the iBook. But with 256MB the iBook is almost twice as
fast! 28.5 MB/s is less than UDMA/33... quite slow...
Both the iBook and PowerBook still have PATA of course, since no serial
ata devices existed back then
the iBook has
[ 3.774751] pata-pci-macio 0002:20:0d.0: Activating pata-macio
chipset UniNorth ATA-6, Apple bus ID 3
[ 3.775921] scsi host0: pata_macio
[ 4.802731] pata-macio 0.00020000:ata-3: Activating pata-macio
chipset KeyLargo ATA-3, Apple bus ID 0
[ 4.810545] scsi host1: pata_macio
I bet the first one is the Hard Disk, the second one is for the optical
drive.
The PowerBook appears also to have the same UniNorth and KeyLargo... so
I doubt there is a driver issue? Apple reused the same chips.
However:
on the PowerBook the ata1 attaches as UDMA/100 ATA-6.
on the iBook I get UDMA/100 ATA-8
Is this ATA-8 all the reason of being faster? Is just the PB using a
slow HD? or it does not negotiate or get recognized to full speed?
Wondering! for both UDMA/100 indicates 100MBytes top speed.
ATA-8 appears to be a hybrid drive... with a cache, I don't think that
part can explain speed up for a 256MB file! internet search says it is
an 8MB cache.
Riccardo
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