I will not put all my trust to one test program as I don't know how it was
wrote, if you only read or write a small file you will not see the truth. My
Pinnacle Studio reported the R/W speed of my SATA drive as 39.6/29.8MB (ok,
it is an old drive) and the USB drive as 29.5/25MB.
Why not simply copy a folder full of files and compare the result? It is how
I use my backup drives.
I'm not arguing the $5 difference, I will also go for the duo version, just
don't belive there is such a big difference (even 3x not to mention 5x).
C.H.Ling
----- Original Message -----
From: "Moose"
> 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.
>>
>
> I have not done any careful comparisons, as a big difference was readily
> apparent just watching the progress of a copy operation. I've now done a
> very simple one. I've compared only read speeds for small pieces of data
> - for the simple reason that my free version of HDTune only does that. I
> think the results are instructive.
> <http://www.moosemystic.net/Gallery/tech/Misc/WDC1500_eSATAvsUSB2.jpg>
>
> Unfortunately, the program also rescales the graph height, so you need
> to look at the vertical scale and/or the numbers on the right. Both
> tests are of the same drive in the same docking station. The top one is
> eSATA. It shows the typical shape, flat at first, then tapering down as
> latency becomes greater as the circumference of the tracks increases
> farther out on the platters. In fact, it's a better than average plot,
> with a long high speed section. As it does slope down slightly right
> from the start, I believe the limitation is the disk itself, not the
> connections.
>
> The second plot is of the same equipment, but using the USB 2.0 HSE
> connection. The dead flat plot is a clear indication that the USB
> connection is the limiting factor in speed. So at least for read speed,
> the 5x raw spec is optimistic for this drive. On the other hand,
> 85.4/27.2 is still 3x. To date, I've only filled part of the 1.5Tb
> drive, so I am still seeing something like the 90 MB/sec part of the
> curve.
>
> But again, the limitation is the drive, not the eSATA connection, so
> this test doesn't say what that might be capable of.
>
> C.H.Ling wrote:
>> 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.
>
> I assume you meant to say "writing time is also *not* very important".
>
> Sure, but the price difference between USB only and USB & eSATA was only
> $US5. So why not go with the faster interface? The docking station can
> handle any 3.5" or 2.5" SATA drive. The possibilities for other tasks,
> where speed could make a difference, are there.
>
> C.H.Ling wrote:
>> My experience is if you have a large set of files to copy the result is
>> quite accurate (did many tests in the pass twenty years), I bet no more
>> than 20% variation in most cases unless your dirve is almost full.
>
> I've never measured that. Frankly, I doubt is I will. It's obvious to me
> from experience that eSATA is much faster. Just how much I don't need to
> quantify.
>
> As Chuck said, such a test is only valid if all drives are defragmented
> before testing.
>
>> To gain more speed you better go with a 10000rpm drive or a RAID setup.
>
> That is much more expensive than a simple eSATA appliance. And the
> higher speed drives don't come in the largest sizes, at least that I've
> seen.
>
> Another other factor to consider is that the 1TB and larger drives use
> vertical recording, so the bit density is higher and any given read
> speed can generate a higher output speed. The drive I tested has that
> advantage. So I added a test of a WD 500GB drive without vertical
> recording to the example. This is an internal drive, directly connected
> to the MB SATA header.
>
> As you can see, the graph starts much lower and drops much faster than
> the 1TB drive. So it appears that the advantage of eSATA may be greater
> for 1TB and larger drives.
>
> Moose
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