On Aug 21, 2010, at 4:58 PM, John Carmonne wrote:

> Hi All
> 
> I recently installed a SeriTek 1V4 in my PM G4 and PM G5 the transfer speed 
> is 88 sec's per GB  on a 114 GB CCC. I was under the impression it would a 
> lot faster than this I seem to remember a 3 GB per min claim. Is it possible 
> I'm doing something wrong? Both HDD's are 2TB 7200 RPM Hitahci's in the PM G5.
> 
> 
You can only go as fast as the drive can read or write, whichever drive is 
slower.  3Gb/s is the maximum transfer rate the interface is capable of.  
Translates out to roughly 300MB/s.  The fastest hard drives on the market are 
only capable of reading at around 80MB/s and writing at around 65MB/s sustained 
transfer.  When you're running CCC, you're also having the processor get 
involved reading, checking, and verifying permissions and metadata on every 
single file copied and parsed.  If you have a bunch of little files, it'll take 
MUCH longer than when you're running large single files like DVD ISO's or large 
movies.  That said, I've always found Hitachi drives to be much slower than 
other brands on the market, so you're likely in the ballpark of what your 
system is capable of doing with the hardware you have installed.  The 1V4 you 
have is also the 1.5Gb/s version, limited to a maximum controller throughput of 
150MB/s theoretical maximum.  If you've got both drives attached to the same 
card, you can insert a bunch of hardware interrupts, etc, and you can see how 
it'll slow down.

SATA isn't magic.  It's still bound by the abilities of the hardware connected 
to it.  All current SATA drives have the SATAII interface which is capable of 
3.0Gb/s (not to be confused with GB/s) yet we still have yet to see a drive 
capable of outperforming the original SATA interface.  Just be patient, it'll 
go as fast as it's capable of going!

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