How do you confirm USB3 is operational

If you connect it to a usb 2.0 port, you should get a pop up on your desktop saying 'this device can perform faster'. You can also transfer the same file from your friends computer to your external and see how long it takes.

I think there is a lot of hype regarding USB3 for spinning disks. Lets look at the facts:

-- USB2 has a maximum transfer rate of 480 Mbps
-- USB3 has a theoritical transfer rate of up to 6 Gbps

However, let's look at the disks

-- Spinning disks (5.400 and 7.200 Rpm) have a transfer rate of 500 to 800 Mbps ( some Raptors may be faster)

So for those disks you will see at best a 60% performance improvement. In fact I made a 22GB image to a USB2 external in 12 minutes and to a USB3 external in 9 minutes. So it was relatively unexciting.

But once we get large SSDs that are affordable for storage, that will be another story.

If they had designed USB 3.0 to be only twice as fast as USB 2.0 it would get maxed out before it got going. With a 6Gbps speed it has lots of room for future growth.

Jim

The easiest way to test it to simply time the transfer of a large file. Get yourself an ISO file or something else which is 1GB or 2GB in size. Copying those files via USB 2.0 would results in about 25 MB/sec. So, a 1GB file would take about 40 seconds to transfer over USB2. A 2GB file would take about 80 seconds to transfer.

If you are using a USB3 device, I would expect that you would get at least 50MB/sec...so a 1GB file would be done in about 20 seconds and a 2GB file would be done in about 40 seconds. If you are going this fast, or faster...it's certainly working.

Most USB 3 devices are limited by the speeds of the hard drive itself...not the bus speeds.

Cr00zng said:

The maximum throughput rate for USB 2.0 is 480Mb/s, or 60MB/s; the maximum throughput rate for the USB 3.0 4.8Gb/s, or 600MB/s.

There's no USB 2.0 device that can achive maximum transfer rate, even the best of them max out at around 320Mb/s, or 40MB/s. That's 2/3 of the maximum transfer rate; the chances are that the USB 3.0 devices will not reach the maximum transfer rate either. They probably will top out at 3.2Gb/s, or 400MB/s. Still an awesome speed and would be faster than the best SATA 3.0, or 6G, SSD drives.

The maximum transfer rate for the SATA 3.0 is 6Gb/s, or 750MB/s. Similarly to the USB devices, the current SSD devices don't even come close to the maximum transfer rate. For example the Crucial C300 series SSD (256GB) has a maximum read speed of 355MB/s and write speed of 215MB/s; not even close to 50% of the SATA 3.0 specification. Don't take me wrong, the SSD devices are a lot faster than any single mechanical drive can ever be, that's not the point.

The point is that neither the USB, nor the SATA devices live up to the specification defined speed. The actual transfer rate is anywhere from less than 50 to about 70 percentile of the specification defined speed. It sort of reminds me of buying 2x4 in the US, that has an actual size of 1.5x3.5...

Your point is well taken. The reason why the max. can normally not be achieved is because the max. refers to the optimal blocksize that is being transferred. But normally the operations do not use these blocksizes.

The best example is the system itself which use a 4k blocksize in many cases. And that is usually far from being optimal - even for a SSD. If you look at the Atto Benchmarks in this thread, you can clearly see that.

If we compare MAX design speed, all the devices fall short. However when you compare operation speeds between USB 2.0 and 3.0, the 3.0 does perform better. I believe the protocol of 3.0 was tweaked to handle the overhead better and this is where the difference shows up. Here is a link to my post from last year. Same external drives tested on 2.0 and 3.0 so the only difference was the interface.

USB 3.0 vs 2.0

If your auto has a max speed of 50mph and mine is 70mph it does not matter if they raise the speed limit from 75mph to 100mph since neither one of us can reach either limit, but my auto still goes faster.

Jim