Performance with Western Digital WD250JB
Before we pass over to testing our USB 2.0 controllers with this hard disk drive, I have to say a few words about the limitations imposed by the Gembird Flexi Drive 2.0 chassis. It turned out that the hard disk drive installed into it cannot be formatted for more than 128GB. Moreover, the documentation for Gembird Flexi Drive 2.0 declared the interface bandwidth of only 40MB/s instead of the 60MB/s theoretically expected from the USB 2.0 interface. All these limitations seem to be implemented on the hardware level, and should be determined by the USB 2.0-IDE bridge used in this chassis.
The HDTach program allowed us to measure the Read Burst Speed of the interface. The advantages of the USB 2.0 bus integrated into the chipset are more than evident here: it leaves not a single chance to the competitors. NEC and VIA controllers work considerably slower, though the NEC one is a little bit faster than VIA.
I cannot say that the integrated controller performed better due to wider access bus to the memory subsystem (as we remember, the USB 2.0 controller of the i865PE chipset is connected directly to the memory controller avoiding the PCI bus). The maximum data transfer rate it achieved made only 30MB/s which is considerably lower than the PCI bus bandwidth of 133MB/s.
The same situation can be observed in IOMark test. All obtained results correlate perfectly well with the performance rates from the previous test. Again the indisputable leadership belongs to the integrated USB 2.0 controller of the Intel’s ICH5 South Bridge: the HDD connected to it appeared the fastest. The second prize is again won by NEC 7200100AGM controller, which is pretty far behind the leader. And the last one of the three appeared VIA VT6202.