USB 2.0 speed too slow? teach you to use USB 2.0 speed fix

With USB3.0 control chip motherboard, although has become the mainstream of the market, but for most users still use USB2.0, USB2.0 file transfer speed also seems to be unable to meet their requirements. In fact, now USB2.0 speed there is room for improvement, we can use the speed-increasing patch to explore the potential of USB2.0.

USB 2.0 Why not reach the 60mb/s?

We all know that the theoretical bandwidth of USB 2.0 is 480Mbps, that is, 60mb/s data transmission rate, but the actual use we will find that the theoretical speed is pit Dad, a long time USB 2.0 maximum actual transmission speed is limited to about 30mb/s, only to reach the theoretical bandwidth of half. This is due to backward protocols and coding patterns.

USB 2.0 is a traditional bulk-only transport (BOT) protocol, because of the lack of improvement, with the current high speed storage devices, the BOT protocol to hinder the speed of the USB transmission problem has emerged. The current USB 3.0 new USB attached SCSI Protocol (uasp) protocol, the addition of two sets of data bus, support for multiple command concurrency and NCQ queue function, so that can play 5Gbps of high-speed bandwidth advantage.

In addition, USB 2.0 uses the NRZI (Non-return-to-zero inverted) encoding, which is based on serial transmission mode, the transmission of consecutive 0, 1 strings, because of the need to force 0 to maintain the transmitter and receiver frequency synchronization will result in USB 2.0 waste of transmission bandwidth. The USB 3.0 uses the popular 8B/10B encoding method, the effective data utilization rate is 80%, namely the USB 3.0 effective data transmission bandwidth is 500mb/s.

Small patch for USB 2.0 big speed

Microsoft currently released a patch to improve the access speed of USB devices, because it is a hotfix hot repair patch, and not as a regular patch with the system automatically updated, so we usually do not realize its role, then we can manually download the installation.

From Microsoft official download windows6.1-kb2581464 patch, after decompression installation. Light installation patch is not enough, you also need to manually modify the registry, the USB 2.0 storage device Maximum transfer value from the default 64KB to 2MB, so that it can improve its speed.

First you need to add the INF device information for the storage device to the registry. Plug the U disk into the computer, locate the current USB 2.0 storage device in the disk drive in Device Manager, right-click it, select Properties, and switch to the Details tab. In the Attribute Drop-down menu, select Parent, and a string of characters appears in the Value dialog box (Figure 1). Where the vid_xxxx&pid_xxxx character is the only INF device identifier for the USB 2.0 storage device, such as vid_090c&pid_1000, or 090c1000.

Run regedit, open Registry Editor, and click to expand Hkey_local_machinesystemcurrentcontrolset controlusbstor. There are several subprojects under Usbstor, create a new item named "090c1000", select it, and then right-click a new DWORD value named "Maximumtransferlength" in the margin to the right of the window, and then double-click to change its value to 001FFFE0 ( As shown in Figure 2, the decimal value is 2097120, which is 2MB. Reboot the system after saving.

Actual test results

I use Yu-Zhan (apacer) AH320 16GB u disk for the comparison before and after the test, first run Atto disk Benchmark, in the default configuration, read and write speed is 32mb/s and 16mb/s, (because of this U disk I produced, write speed down, The original did not have the capacity to read and write speed for 32mb/s and 22mb/s) after the installation patch has a significant increase in read and write speed, the highest read reached the 41mb/s, write speed is also 29mb/s. Although this rate in the USB 3.0 is a pediatric, but for those USB 2.0 old users without upgrading USB 3.0 under the premise of getting 40mb/s above the read transmission speed, relative to the default environment or a small breakthrough, can save a lot of time to copy files. Written in the end for users who are still using USB 2.0 devices, it is also a good thing to accelerate the speed of the data transfer and to gain free transfer performance without upgrading. Of course, this acceleration mode also applies to USB 3.0, which improves its transmission performance.

Small note: If you have more than one USB disk or flash memory, each storage device INF device information to be added to the registry. After many tests, this patch is mainly for U disk, SD card reader is basically invalid. For users who are still using USB 2.0 devices, it is also a good idea for them to accelerate the time they can save for data transmission and to gain free transfer performance without upgrading. Of course, this acceleration mode also applies to USB 3.0, which improves its transmission performance. USB 3.0 is also based on Bot transport protocol, but based on 5Gbps high bandwidth, only the use of SSD such high-speed equipment, speed before and after the transmission speed difference will be more obvious.

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