Finalized in 2001, Universial Serial Bus (USB) 2.0 is a complete overhaul of the Universal Serial Bus input/output bus protocol which allows much higher speeds than the older USB 1.1 standard did. The goal of the new serial bus is to broaden the range of external peripherals that can be used on a computer. A hard drive can easily hit the USB 1.1 bottleneck whereas it now becomes more 'usable' under USB 2.0 conditions.
You can identify whether your PC has Hi-Speed USB or not relatively easy. Open Device Manager and expand the Universal Serial Bus section. There should be an "Enhanced" USB host controller present.
Windows 98 systems may use a different name, because Hi-Speed USB drivers in these operating systems are not provided directly from Microsoft (Windows ME, 2000 and XP get their drivers through Windows Update).
These drivers are provided by the manufacturer, and may carry the maker's name (i.e. ADS, Belkin, IOGear, Siig, etc.). There should also be two "standard" version USB host controllers present as well. They are embedded in the USB chip which routes the differing USB speeds accordingly without user intervention.
There are currently 7 manufacturers of the Hi-Speed USB host silicon themselves:
ALi (Acer Labs)
Intel
NEC
SiS
VIA
nVidia (shows as "Standard" controller)
Philips
SB 1.1 allowed a maximum transfer rate of 12Mbits/second. It is now obsolete, but both of its speeds (1.5Mbps & 12Mbps) are being adopted into USB 2.0, and they are now called Original USB officially. Though some manufacturers label their products Full-Speed USB. Note that this seems a bit deceptive as it's easy to mistake Full-Speed for Hi-Speed. You won't be fooled from now on as you now aware that Full Speed USB is only 12Mbits/second where Hi-Speed USB mode is capable of a much faster 480Mbits/second.
Traditionally, USB mice and keyboards only need 1.5Mbps to function; exceptions are gaming input devices that require 12Mbps, and they include the Logitech G5, G7, G15 and Razer Copperhead. These higher-end gaming products send way more location feeds thru USB; hence, more bandwidth is required. Generally, the performance levels (1.5Mbps & 12Mbps) are grouped under 'Original USB' by the USB Promoter Group.
The logo shown on the right is authorized by the same organization to the vendors for use on their products should they passed the compliance tests.
USB 2.0 has a raw data rate at 480Mbps, and it is rated 40 times faster than its predecessor interface, USB 1.1, which tops at 12Mbps. Originally, USB 2.0 was intended to go only as fast as 240Mbps, but in October 1999, USB 2.0 Promoter Group pumped up the speed to 480Mbps.
As far as we know, effective rate reaches at 40MBps or 320Mbps for bulk transfer on a USB 2.0 hard drive with no one else is sharing the bus. Flash Drives seem to be catching up too with the some hitting 30MB/s milestone. For all we know, USB interface could become become the bottleneck for flash drives as early as 2008.
Additional notes from Alex Esquenet - our engineer friend based in Belgium: "A fast usb host can achieve 40 MBytes/sec. The theorical 60 MB/sec cannot be achieved, because of the margin taken between the sof's (125 us), so if a packet cannot take place before the sof, the packet will be rescheduled after the next sof. On top of that, all the USB transactions are handled by software on the PC. For instance, a USB host on a PCI bus will send or receive the data via the PCI bus; the stack will prepare the next data in memory and receive interrupt from the host."