I don't think it's overhead per say, but I think that USB stuff goes through the CPU where other things like firewire and eSata do not.
I'm not sure of technical reasons, but it's the same reason that Firewire 400 outperforms USB 2.0 (which is 480mbps). Technically USB 2.0 should be faster, by 80mbps.....but it's been shown time and time again that firewire is more efficient and goes faster.
I don't have any numbers but I believe the reason given that a PCI express card can outperform USB 3.0 built into the motherboard is that the cards typically have a processor that handles the overhead.
My WD Caviar Black 64 MB cache 6 Gb/sec drive is rated by the manufacturer at a max sustained read speed of 126 MB/sec. Crystal Disk Mark shows sequential read of 138 MB/sec but that's because CDM considers 1 million bytes per second as 1 MB/sec. I imagine WD uses 1024 kb /sec. when they talk about 1 MB/sec. throughput.
However you measure it, I don't think you can call it "slow" when you watch the progress bar just zip across when copying a GB video file.
I own two identical WD Passport 0730 1TB drives with USB 3 capability and I own a USB 3 card with a single USB 3 port.
So one HD is connected to the USB 3 port and the other a standard USB 2 port.
Like many of you, I was very curious to see if USB 3 made much of a difference, and as I had two identical drives I figured I had the perfect way to test. So I ran HD Tune on both WD drives as well as my internal eSATA Samsung 500 gig drive.
FIRST WD CONNECTED WITH USB 2:
[IMG]file:///C:/Users/Nick/AppData/Local/Temp/moz-screenshot.png[/IMG][IMG]file:///C:/Users/Nick/AppData/Local/Temp/moz-screenshot-1.png[/IMG]
HD Tune Pro: WD My Passport 0730 Benchmark
Test capacity: full
Read transfer rate
Transfer Rate Minimum : 15.3 MB/s
Transfer Rate Maximum : 16.4 MB/s
Transfer Rate Average :
Access Time :
Burst Rate :
CPU Usage :
SECOND WD CONNECTED TO USB 3:
HD Tune Pro: WD My Passport 0730 Benchmark
Test capacity: full
Read transfer rate
Transfer Rate Minimum : 32.8 MB/s
Transfer Rate Maximum : 75.9 MB/s
Transfer Rate Average :
Access Time :
Burst Rate :
CPU Usage :
INTERNAL SAMSUNG 500 GIG DRIVE W/ eSATA:
HD Tune Pro: ST3500418AS Benchmark
Test capacity: full
Read transfer rate
Transfer Rate Minimum : 65.8 MB/s
Transfer Rate Maximum : 102.2 MB/s
Transfer Rate Average :
Access Time :
Burst Rate :
CPU Usage :
So clearly USB 3 IS indeed superior to USB 2, that much is clear. And perhaps some people may find this helpful if they are having problems with their USB 3 drives and what to expect speed wise.
But the surprising thing is that eSATA seems to be the clear winner. Of course, this may have to do with the speed of the Samsung drive so the IDEAL test would be to have THREE identical drives and connect them up to all three ways and compare speeds.
I DEFINATELY notice the speed increase with my USB 3 drive. As you can see, it is three times faster than a standard USB 2 connected drive, but still not as fast as eSATA.
If you are not getting 70+ MB/S with your USB 3 connected drives, clearly something is wrong.
Hope this helps,
Nick
A Simple Test....
I own two identical WD Passport 0730 1TB drives with USB 3 capability and I own a USB 3 card with a single USB 3 port.
So one HD is connected to the USB 3 port and the other a standard USB 2 port.
Like many of you, I was very curious to see if USB 3 made much of a difference, and as I had two identical drives I figured I had the perfect way to test. So I ran HD Tune on both WD drives as well as my internal eSATA Samsung 500 gig drive.
FIRST WD CONNECTED WITH USB 2:
[IMG]file:///C:/Users/Nick/AppData/Local/Temp/moz-screenshot.png[/IMG][IMG]file:///C:/Users/Nick/AppData/Local/Temp/moz-screenshot-1.png[/IMG]
HD Tune Pro: WD My Passport 0730 Benchmark
Test capacity: full
Read transfer rate
Transfer Rate Minimum : 15.3 MB/s
Transfer Rate Maximum : 16.4 MB/s
Transfer Rate Average :
Access Time :
Burst Rate :
CPU Usage :
SECOND WD CONNECTED TO USB 3:
HD Tune Pro: WD My Passport 0730 Benchmark
Test capacity: full
Read transfer rate
Transfer Rate Minimum : 32.8 MB/s
Transfer Rate Maximum : 75.9 MB/s
Transfer Rate Average :
Access Time :
Burst Rate :
CPU Usage :
INTERNAL SAMSUNG 500 GIG DRIVE W/ eSATA:
HD Tune Pro: ST3500418AS Benchmark
Test capacity: full
Read transfer rate
Transfer Rate Minimum : 65.8 MB/s
Transfer Rate Maximum : 102.2 MB/s
Transfer Rate Average :
Access Time :
Burst Rate :
CPU Usage :
So clearly USB 3 IS indeed superior to USB 2, that much is clear. And perhaps some people may find this helpful if they are having problems with their USB 3 drives and what to expect speed wise.
But the surprising thing is that eSATA seems to be the clear winner. Of course, this may have to do with the speed of the Samsung drive so the IDEAL test would be to have THREE identical drives and connect them up to all three ways and compare speeds.
I DEFINATELY notice the speed increase with my USB 3 drive. As you can see, it is three times faster than a standard USB 2 connected drive, but still not as fast as eSATA.
If you are not getting 70+ MB/S with your USB 3 connected drives, clearly something is wrong.
Hope this helps,
Nick
I know this post is old but my information is relevant.
I have recently been having problems with pci-x USB3.0 cards, when connecting the drives sometimes I was getting a pop-up that the drives could run faster on USB3, the drives were dropping out and on one card i was only getting a USB2 connection on one drive and no connection on the other, It turned out that my mega $$ Antec power supply which was a fear years old had cheap bad capacitors and was not giving a full 5volt on the 5volt rail so I put a new PSU in and now my USB3 cards all work properly and allow the drives to run at full speed IE: 100+mb's.
I will add that I have two USB3 cards, a 2 port Renesas and a four port VIA card, the Renesas card has reduced transfer speed across the ports yet the VIA card does not lose any speed.
That is interesting information. I was always an Antec fan. But who knew that they use cheap components.
I can't really add much to this discussion I'm not very technical, however I also have a Gigabyte motherboard with usb 3.0. As someone already stated copying between 3.0 drives does achieve the speeds as SATA to usb 3.0 or even 2.0 to 3.0 at least in my experience.
I've only read the first to pages so I'm not sure if this has already been brought up. I don't want to offend you either but my 3.0 drives came with two cables for 2.0 and 3.0 make sure your using the 3.0 cable and have the drivers installed. :)
Hey!! I ve been having problems lately with my external hdd! I d be glad if anyone could help me out! it's a transcend storejet 25M3 usb 3.0!Of late the transfer rates are very slow while copying a file from the PC to the hard disk!usually around 1MBps.
Thank You!!
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