Which is faster: copying from mounted AOMEI image or from external HD via USB 2?

[dr_andus]

I need to copy over a few hundred Gigs of data back onto my PC's hard drive and was wondering which is faster:

• copying from mounted AOMEI image or
• from external HD via USB 2.0?

I'm currently copying via the mounted image, and some 200+ Gigs are predicted to be copied over in about 2 hours.

Am I correct to assume that via the AOMEI image should be faster, as it's done internally and there is less hardware, wires etc. involved, which should make it faster than external HD, USB 2.0 cable etc.?

[tomos]

I dont know.
You could try figuring it out --

• USB2 has a 60MB a second limit -- but the problem is it often only reaches ~30 maximum -- will depend on your external drive and file sizes
• 1GB is 1,000MB ....
• Aomei's 100GB per hour would be ~28MB.p.s. if I'm correct

I wouldnt bother starting again - would probably be about the same rate.

[dr_andus]

• Aomei's 100GB per hour would be ~28MB.p.s. if I'm correct

-tomos (September 22, 2015, 08:39 AM)

Thanks. I just checked in the Dopus popup and for the AOMEI transfer it says

• average: 11.5 MB/s
• peak: 39.3 MB/s

I'm waiting to do another batch, so I'll do that via the USB 2.0 and compare.

[dr_andus]

OK, this was a bit counterintuitive, but it looks like the USB 2.0 transfer was quicker for some reason:

• average: 15.9 MB/s
• peak: 38.6 MB/s

[tomos]

OK, this was a bit counterintuitive, but it looks like the USB 2.0 transfer was quicker for some reason:

• average: 15.9 MB/s
• peak: 38.6 MB/s

-dr_andus (September 22, 2015, 10:18 AM)

good to know
it's possibly because Aomei is trying to get the files out of a compressed image

[4wd]

You didn't say whether the mounted image is on the same internal drive as the copying destination.  If it is then the constant head seeking of the drive is going to slow things down a lot and you'd be better off copying from the external USB drive.

[f0dder]

USB2 has a 60MB a second limit -- but the problem is it often only reaches ~30 maximum -- will depend on your external drive and file sizes

-tomos (September 22, 2015, 08:39 AM)

The raw USB2 link has a 480Mbit/s theoretical limit, yes, but because of protocol overhead you'll never ever reach that - and the (kind of) people who saw it fit to use the theoretical link limit as advertisement should be dragged out back and done with.

Theoretically one should be able to reach about 35MB/s of "interesting" bandwidth, but it's usually in the 25MB/s ballpark.

[dr_andus]

You didn't say whether the mounted image is on the same internal drive as the copying destination.  If it is then the constant head seeking of the drive is going to slow things down a lot and you'd be better off copying from the external USB drive.

-4wd (September 22, 2015, 05:09 PM)

Indeed, that was the case. Thanks for the explanation!