USB 3.0 has an upper limit around 5.0Gbps. SATA III has an upper limit of 6.0Gbps. Regardless of overhead these rates are far higher than what a mechanical HDD can sustain for large transfers.
Most mechanical HDDs won't be able to sustain more than about 1.5Gbps (HDD Speed results). So I doubt y...
this answer, post altered after getting quite a bit of rep, failed to acknowlege some of the "issues" of having 2 "controllers" 2 "buffer" sets, and a large dependancy on type of "speed" were talking about.
It did not stop anyone from upvoting it.
While moab says , ya sure about 1/2 that. I do not think that is valid either.
When it is less direct connections, you can get full possible speeds going, with something like a large sequential item. but more latencies can exist, in the whole paths and connections.
A good test should represent some semblance of a reality :-) even have some IwhileO and some random, and some big stuff, and the actual copying of both big and small files. Doing that i would Never put a drive on a usb 3.0 vrses and internal intel controller.
If it is a backup drive, then it really should be at least able to be powered off manually or disconnect manuely . even if that is after you find a virus on your system :-)
It is kinda weird to see people worrying themselves silly (at times) over 1-2% numbers on video cards, and CPU overclocking and all, which can include one card doing 15%+ better in one game and the other the same in a different game. Then the disk, to know there is variations of 10%+ in various operations of controllers and connections, but that All out bottleneck :) not being tested daily.