Mar 25, 2012 Written by: ROG

What Is ASUS USB 3 Boost And UASP?

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USB 3.0 Boost is a unique feature specially offered by ASUS allowing users to unleash the real performance of their USB 3.0 by offering two new features: an new industry standard called UASP and also an ASUS-developed method of overclocking the USB 3.0 bus called Turbo Mode, which boosts performance even when UASP-enabled devices are not available.

Some terms of use before starting:

USB 3.0 Boost - ASUS' overall technology used to describe the incorporation of UASP and Turbo Mode drivers and AI Suite II software.

Turbo Mode - 'Optimized' BOT mode developed by ASUS, which improves the performance of standard USB 3.0 hardware

UASP Mode - A new industry standard of USB 3.0.

Native Support of UASP (USB Attached SCSI Protocol)

The adoption of the SCSI Protocol in USB 3.0 provides its users with the advantage of having better data throughput than traditional BOT (Bulk-Only Transfer) protocol, all thanks to its streaming architecture as well as the improved queuing (NCQ support) and task management, which eliminated much of the round trip time between USB commands, so more commands can be sent simultaneously. Moreover, thanks to the multi-tasking aware architecture, the performance is further enhanced when multiple transfers occur.

The downside of UASP is that the receiving device (Flash drive/external hard drive etc) must also be UASP enabled for the protocol to work. This requires checking your peripherals before purchase. However since UASP is an industry standard, the device support for ASUS UASP implementation is not restricted to a particular controller manufacturer or device type, so the overall number of peripherals available should undoubtedly grow.

Turbo Mode (Optimized Bulk-Only Transfer) Support

Optimized BOT, as you can guess from the name, does not have the luxury of UASP advances and relies on the standard BOT protocol currently used by all USB 3.0 devices. This means it may not help to further improve the transfer performance when multiple files were transferred at the same time, however, it still delivers a noticeable performance gain in USB 3.0 data reads with the ASUS Turbo Mode. This is thanks to its improvements in data streaming, where much of the round trip time between command phases is reduced. The other advantage of having the ASUS Turbo Mode is the fact that it supports all USB devices understanding the SCSI command, rather than restricting the support to UASP enabled devices only, making it more accessible for most users.

Automatic Switching & Monitoring via AI Suite II

Whether you are using a UASP enabled device or standard BOT one, the ASUS software automatically checks to see what protocol it should use. If UASP is present, then it will use it, otherwise the software will enable traditional BOT instead.

What mode is currently in use can be seen via AI Suite II. The software has a USB 3.0 Boost tab which shows which of the two modes are currently enabled for each USB 3.0 port.

Background knowledge of the existing USB 3.0 Protocol

The current USB 3.0 Protocol was established in 1998, since the launch of USB 1.1. At this time the throughput was low, multitasking was limited and no multiple access to the same device was even considered. Since then, these issues have created a bottleneck for modern user modes, especially with USB 3.0, when the bandwidth is the same as its internal rival: SATA technology. The standard BOT (Bulk-Only Transfer) architecture used from USB 1.1 through to USB 3.0 is shown below:

Don't worry if you haven't done a degree in Electrical Engineering, the above illustration basically shows that the traditional BOT protocol can only handle one request at a time. It needs to wait for the device to complete its task before more data can be transmitted. Since USB 1.1, each revision of USB (2.0, 3.0) has compensated for its inherent limitation by enlarging the size of data packet, so more is transferred each time, as well as the introduction of the USB3.0 cache found on all USB 3.0 controllers allowing the USB 3.0 device to 'fool' the PC into thinking its task is done and it can accept more data.

How does UASP work?

UASP on the other hand completely restructures the USB transmission protocol, targeting the weaknesses of traditional BOT through the following approaches:

Again decrypting the complicated image above: the entire data transmission has been divided into four different pipelines, Status (what are you doing now?), Command (what do you want me to do?), Data-in (Postman delivery), and Data-out (Visiting the postbox). This allows multiple commands to be issued at the same time, while also a small chunk of data is collected in data buffer, and repacked into a larger data packet to be streamed through. This brings the speed up in small data block access, as well as less CPU utilization thanks to the reduction in the number of transmissions. Moreover, with the capability to process the data of the commands in the order they arrive rather than the order they were sent out also minimizes the waiting time, providing the new architecture room to squeeze in more data packets. Basically all this means you can push more data through at once!

Finally, the pipeline architecture also allows multiple data transmissions to use up the entire bandwidth available to the device, bringing a significant difference to performance of multiple transfers compared to BOT.

System Requirements:

Hardware requirement:

  • 1 x Asus motherboard supporting USB 3.0 Boost functionality.
  • 1 x USB 3.0 enclosure based on any one of the following chipset listed below when testing UASP. Note this list will actively grow as more UASP enabled chipsets come to market:

- LucidPORT USB300-REV2
- ASMedia ASM1051E
- ASMedia ASM1051U
- ASMedia ASM1054

  • 1 x SSD to be installed on the USB 3.0 enclosure to be used as the source disk.

Software requirement:

  • Windows XP, Vista or 7 32bit or 64bit OS
  • USB 3.0 driver preinstalled
  • ASUS Ai Suite II software package preinstalled

1. For the accuracy of results, it is advised to conduct a secure erase for all SSDs (both the source and destination) before conducting the test.
2. The performance gain is less noticeable when using USB 3.0 HDD or USB pen drive, as the throughput potential of such devices are within what can be provided by the existing BOT architecture for USB 3.0.

Test procedures:

1. Open up Ai Suite II, and click on the [USB 3.0 Boost] from under [Tool]:

2. Select the desired device, followed by the mode selection button to switch between different modes:

3. Logo will change to indicate the status of the USB 3.0 device:

Which motherboards are compatible?

For the last 9 months ASUS has been making USB 3.0 Boost enabled motherboards. See our USB 3.0 boost event site for more details of which motherboards are supported.

Go ahead and give this guide a try and tell us your results in our ROG forum.

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