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garycurtis

macrumors 6502
Original poster
I'll soon be getting a new iMac. My ext. backup is a LaCie quadra, via Time Machine. The port on the iMac is USB 3. Should I use a USB cable to connect the two?

I'm wondering if the bottleneck would be the spinning disk, or data rate of the cabling.

It would be USB 3 > USB 2. Or should I spend $$$ to get a USB 3 > eSata adapter?
 

hallux

macrumors 68040
Apr 25, 2012
3,437
1,005
Depending on the disk, your limitation may be disk-related. Where does the eSATA come in? If you take the disk out of the enclosure you'd need another enclosure to make the disk USB again. eSATA requires a port on the computer to get eSATA speeds.
 

garycurtis

macrumors 6502
Original poster
Thanks, Hallux. The name of the drive, LaCie Quadra, denotes that the enclosure has 4 possible connectors. FW400, FW800, eSata and USB. The USB is USB-2. Self enclosed in a case with a power supply and operating LED indicators.

I currently use the eSata connection because it is the fastest. I want to keep it for Time Machine backups. So is the disk itself the limiting factor, or should I spend money to enable the fastest connector? Which would be eSata routed to USB 3 on the iMac.
 

hallux

macrumors 68040
Apr 25, 2012
3,437
1,005
You're confusing things. eSATA and USB are both connection types for external devices. You don't "route eSATA through USB 3.0". If you want USB 3.0 connectivity on the drive, replace the enclosure.

eSATA

USB 3.0
 

garycurtis

macrumors 6502
Original poster
I guess the terminology used is leading this astray. Instead of saying "route", I simply want to connect the USB 3 plug on the new iMac to the eSata plug on the housing of my ext. LaCie 1Tb drive. Using the kind of cable for peripherals.

The LaCie has power, cooling, logic, on-off switch and LED indicator. It is a self-powered, stand alone ext. HDD. Not a bare disk.

I want a cable with USB 3 on one end, and eSata on the other. Or I could accept the speed loss and USB 3>USB 2 on the cable.
 

garycurtis

macrumors 6502
Original poster
Thanks. Exactly the answer I sought. On the eSata end of the cable the I/O limit is about 50% greater than FW800. Or, about 1.2Gb/sec.

Would that be the limit of a USB3/eSata connector? Do you think a 7200 rpm spinning disk warrants USB 3 connectivity?
 

chown33

Moderator
Staff member
Aug 9, 2009
10,706
8,348
A sea of green
Thanks. Exactly the answer I sought. On the eSata end of the cable the I/O limit is about 50% greater than FW800. Or, about 1.2Gb/sec.

Would that be the limit of a USB3/eSata connector? Do you think a 7200 rpm spinning disk warrants USB 3 connectivity?

The upper limit of any adapter is always going to be the slower of the interfaces, not the faster.
 

garycurtis

macrumors 6502
Original poster
The Amazon link posted by Peace had this user review below the item:

My laptop and desktop have both been upgraded to support USB 3.0 (4.8Gbps). I had an external 2TB drive with USB 2.0 and eSATA interfaces, but no eSATA ports on my PCs. Used the BYTECC USB3-ESATA adapter and an eSATA cable (purchased separately) to connect the external drive to a USB 3.0 port on my laptop. My backups now write to the external drive more than three times as fast than when using USB 2.0.

Great news to my ears.
 
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