I initially used 3.5 external drives for backup because they were higher
capacity and much cheaper. However, I switched to 2.5 drives over a year
ago. My first drives were 500GB Acomdata from NewEgg that included an e-SATA
interface. This makes them a bit faster than you can get from a USB 2
interface. Note that any USB 2 drive will be limited to 30MB/sec transfer
speed. In practice, I have often seen the actual speed to be as low as
10MB/sec due to other system constraints.

Presently I have two Acomdata 500GB USB/e-SATA drives, two Seagate FreeAgent
Go 500GB drives, and one Seagate FreeAgent Go 1TB drive - all are 2.5 inch
size. The 1TB drive is physically larger in that it is thicker than the
500GB. In USB (not e-SATA) operation, I have found the Seagate to be
somewhat faster than the Acomdata drives. Note that of the two Acomdata
drives, I have one that contains a Samsung HD, and the other has a Western
Digital HD. Both work similarly.

I have had no problems powering the drives even from an older laptop. YMMV.
If you have a USB 3 interface on your computer, or are planning one, you may
consider one of the newer USB 3 drives. This would probably give you double
the transfer speed. With USB 3 the bottleneck would be with the drive and
not the USB interface.

Hope this helps.

Peter Shkabara
-------------------------
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-----Original Message-----
From: Tom [mailto:[log in to unmask]] 
Sent: Saturday, October 02, 2010 6:45 AM
Subject: External HD

I need to get an ext. HD for back up. Looking at a 2.5" model that gets it's
power from the USB. Primary use is auto back up of desktop. Also want to
manually back up wife's desktop and a laptop. I assume I can auto back up my
desktop AND create separate folders to manually back up 2 other computers.

I think the smaller, USB powered HD is more portable and limited use backing
up the laptop will not strain the battery (mostly use laptop plugged in
anyway)

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