If you’ve bought a computer in the last year or two, odds are that it has at least one blue USB port on it, signaling that you’re looking at a SuperSpeed USB port capable of data transfers up to 5 Gbps.
That port’s going to start looking dated soon. The USB 3.0 Promoter Group just approved the new USB 3.1 specification — and it supports data speeds up to 10 Gbps.
For reference, old school USB 2.0 connections can only handle data transfers up to 480 Mbps — which was a huge improvement over USB 1.1, which topped out at 12 Mbps.
Long story short, data transfers between your PC and USB flash drive or hard drive are going to get a lot faster in late 2014 or so — but they’re already way faster than they were a decade ago.
USB 3.1 will be backward compatible with older devices, so just because a system has a USB 3.1 port doesn’t mean you won’t be able to plug in a USB 2.0 flash drive to transfer data. It just won’t be as fast as it could be.
Incidentally, Intel’s latest Thunderbolt technology is capable of even higher data transfer rates of up to 20Gbps, but it’s a more expensive technology which is less likely to be widely adopted by companies that aren’t called Apple.
More important would be whether it brings in any of the USB Power Delivery spec (10x) . Sounds as if it doesn’t. Totally putting aside their 100W notebook-charging goal it’d be nice just to have a standardized 5v >2 amp or 5v/12v 3A port at long last
“Alongside the speed improvements, USB 3.1 also brings new power delivery profiles (as previously reported) that allow for up to 100W to be sent through a USB cable. In theory this allows laptops to charge through new, “detectable” USB cables attached to high-powered hubs such as TVs or desktop PCs, and can remove the necessity to use power bricks for external 3.5-inch hard drives.” https://www.techspot.com/news/53457-10-gbps-usb-specification-finalized-as-usb-31.html
I was just about to buy a USB 3.0 expansion card for my desktop PC. Maybe I’ll wait for a 3.1 card instead. I do use the one on my laptop all the time though with one of my external HD’s. I don’t know why they don’t do away with USB 2.0 ports altogether. It can’t be that much cost difference to include 2 USB 2.0 ports and 1 USB 3.0 port in a laptop…just make them all USB 3.0’s.
I have a USB 3.0 port and have never reached 5 Gbps, sounds good anyway.
Present specification bandwidth limit for 3.0 is 625Mbps but actual device usage usually tops off at around 400Mbps.
Mind, there’s a difference from max bandwidth and what performance you actually get…There’s always overhead and the max given is basically theoretical…
So not too different from how they advertise storage capacity by giving the unformatted capacity instead of the formatted capacity you’d actually use…
Mind the conversion too… The 5 is for Gigabit/s but the 625 is for Megabyte/s
The actual conversion is 625 Mbps = 4.8828125 Gbit/s… So they also round it off to 5…
Here’s a site with a conversion calculator…
To actually get 5 it has to be 640Mbps… but with overhead, etc. it goes down to about 3.125 Gbit/s… but the new spec means it’ll be at least faster than the previous max theoretical limit…
Did you mean to say MBps (megabytes/second) as in 625 MBps
and not Mbps (megabits/second)?
Yes, sorry if that wasn’t automatically clear…
You should to learn more about decimal/binary SI units and bit/byte abbreviations.
b is bit and B is byte.
1 Byte = 8 bits
MiB (mebibyte) = 1024 bytes
MB (megabyte) = 1000 bytes
5 Gbps = (5e9/8/1e6) MBps = 625 MBps (There is no rounding you mentioned)
Also, USB 3.0 uses 8b/10b encoding so the actual message rate is 500 MBps. The protocol overhead brings it further down to ~400 MBps.
The rest of the data rate drops are due to the media’s data rate and host/device controller implementation.
No, do the math… Each Byte does not go equally into each Bit… Those 24 add up!
This is why I linked the site with the conversion calculator… it shows the actual numbers!
That site is mixing up decimal and binary SI units. It’s calculating MiB but giving MB as the units. I did do the math (I even should you the eqations). Now so should you. You don’t need some wrongly coded website calculator to do it.
Okay, you’re right… whoever set up that site messed up.
Anyway, out of the 625 though, devices have only shown up to 400… So that’s a fair bit of overhead.
Yes it’s a lot of overhead. The USB 3.0 spec calls it out too: https://www.usb.org/developers/docs/usb_30_spec_070113.zip
“SuperSpeed efficiency is dependent on a number of factors including 8b/10b symbol encoding,
packet structure and framing, link level flow control, and protocol overhead. At a 5 Gbps signaling
rate with 8b/10b encoding, the raw throughput is 500 MBps. When link flow control, packet
framing, and protocol overhead are considered, it is realistic for 400 MBps or more to be delivered
to an application.”
However, compared to some other protocols it’s not too bad. There are some protocols for other types of media that can reduce the message rate by half or more.
Also depends on application… things like connecting to a external video card isn’t something USB is intended for without adding extra hardware but Thunderbolt can…
Thanks for the clarification…
Also, note that in communication protocols the decimal SI units are usually used especially when using bits per second.
감사합니다 for the explain
thunderbolt is not apple’s baby is intel’s …. Apple just uses it . It’s great tech but I find it more for the
Whoops… right you are. I’ve updated the post.
Hehe, thanks Brad! You need any collaborators?
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