Just look at the (theoretical) bandwith[s].
USB 1.1 --> 12MBit/s = 1.5MB/s (and depending on the hardware and drivers it doesn´t even reach half of that speed... I didn´t ever saw one unit, which brings atleast 1MB/s on a PS2. ~700KB is/was the max.)
USB 2.0 --> 480MBit/s = 60MB/s (a lot more)
PS2-DVD 4x = ~43,5MB/s = ~5,4MB/s
PS3-BD 2x = 72MBit/s = 9MB/s
MPEG2 (Videocompression used on PS2) --> ~10MBit/s = ~1.25MB/s
h.264/AVC (VC used on PS3) --> ~54MBit/s = ~6,75MB/s