Recently saw a video, saying "U disk plugged in slow speed will also be slow" thing, originally Xiaobian thought this was a joke ~
But looking at the bullet screen and comments, I had to have a little doubt in my heart: is the U disk insertion speed really the read and write speed? What do you think about that?
In order to judge the true and false, Xiaobian began the road of seeking truth.
Saw in a post: If you slowly plug in a USB 3.0 device, it will be recognized as USB 2.0. Even gave the principle, oh open is really so magical ~
As shown in the following figure,
USB 3.0 is similar to USB 2.0, except that USB 3.0 adds a set of signal cables with exactly the same 4 pins on the outer front.
Simulating the process of inserting a USB stick into a computer, the first contact is the USB 2.0 pin, at this time the system will have a process of identification and pre-connection, the process is very short. If the USB3.0 signal line is connected during the identification process, it can be judged as a USB3.0 device.
However, if the insertion process is super invincible and slow, and it has exceeded the time of the identification process, then the system is likely to start official work in the USB 2.0 protocol.
The gap between the interface speed of USB 3.0 and USB 2.0 may have been experienced by everyone. Friends who are accustomed to USing USB 3.0 will stomp their feet in a hurry when using USB 2.0, especially when transferring large files. Let's take a detailed comparison chart and visually understand the gap between the two:
According to this principle, and Xiaobian has personally tested, it is indeed confirmed that the U disk is inserted slowly and will be slow!
But this has a premise, this "plug is slow", how slow is the speed? This is not easy to explain. All in all, in general, our normal use will not occur in the situation where the USB 3.0 device is recognized as USB 2.0, unless you have been grinding and rubbing and missing the time for recognition detection.
After understanding, you must learn to "quickly cut the mess"! Don't make USB 3.0 read slow and unclear