Probably a fair test if the drives were otherwise fairly empty such that
the source data was relatively sequentially organized on the drive.
Otherwise, if the data was scattered on one drive and not the other,
seek and rotational delays would be greater on the drive with the
scattered data.
Chuck Norcutt
C.H.Ling wrote:
> Sorry, overlooked the second part. I did the comparison by copying SATA to
> USB and SATA to SATA with the same 20GB data. I have not tried to check the
> Read rate only.
>
> C.H.Ling
>
> ----- Original Message -----
> From: "C.H.Ling"
>
>> So when we are talking about external drives for backup, then writing time
>> is also very important, eSATA does not has that much advantage here.
>>
>> C.H.Ling
>>
>> ----- Original Message -----
>> From: "Chuck Norcutt"
>>
>>> AS I said the other day, disks spend a lot of time just trying to get to
>>> were they're going and, once they get there, waiting on the correct data
>>> to rotate around to where the head is. They all seek to where they're
>>> going at very similar rates and, assuming the same RPM on the platters,
>>> they all wait at the same speed. Actual data throughput gets dragged
>>> down by all the mechanical delays.
>>>
>>> But do be aware of what you're comparing. If you are simply reading
>>> from the USB drive into memory but reading and writing between the two
>>> SATA drives then the write operation has the SATA drives at a big
>>> disadvantage. Writing takes longer than reading and the reading from
>>> drive 1 can't go any faster then the writing to drive 2 once the cache
>>> is full.
>>>
>>> Chuck Norcutt
>>>
>>>
>>> C.H.Ling wrote:
>>>> 5x! Did you ever made a real comparison? I got 22MB per second for USB
>>>> and I
>>>> can't get over 30MB with SATA to SATA (two hard disks inside the same
>>>> PC). I
>>>> believe the HD sustain rate and other overheads in the computer limited
>>>> the
>>>> data rate a lot.
>>>>
>>>> C.H.Ling
>>>>
>>>> ----- Original Message -----
>>>> From: "Moose"
>>>>> I'm simply not buying any external HD which is USB 2.0 only. eSATA is
>>>>> WAY faster, 5x the speed, and only a very few $ more, if that. Maybe it
>>>>> shouldn't make a difference for a drive planned for backup use only,
>>>>> but
>>>>> it does for me. I simply find it easier when the process goes faster.
>>>>>
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>
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