Performance - HD Tune Write Benchmarks
I tested the three drives using both HD Tune Pro and my standard Vista SP1 file copy test. Since HD Tune Pro operates from RAM, the test system's hard drives don't get involved and can't limit performance. Let's look at Write results first.
The plotted line represents write speed in MBytes per second (MB/s), plotted across all sectors of the drive. Since the outer sectors of a disk have a higher rotational velocity, we can assume that the test moves from the outer (0%) to inner (100%) to inner sectors.
The Buffalo drive (Figure 6) hums along just shy of 90 MB/s for most of the sectors and averages 84.3 MB/s. Access times (represented by the yellow dots) have a nice, tight distribution.
Figure 6: Buffalo DriveStation USB 3.0 - HD Tune Benchmark Write
The Seagate (Figure 7) is also pretty steady, but write speeds run about 10 MB/s lower and average out to 72.3 MB/s. Access times are a bit more dispersed than the Buffalo drive.
Figure 7: Seagate BlackArmor PS 110 USB 3.0 - HD Tune Benchmark Write
The WD drive (Figure 8) has the highest write throughput variation of the three and widest dispersion of access times. The large dip, which depresses the average somewhat, was seen in a different spot in a second run. Average write comes in at 73.4 MB/s.
Figure 8: WD MyBook 3.0 - HD Tune Benchmark Write
Moving on to read performance, the Buffalo drive (Figure 9) again has the tightest access time distribution and average speed of 95.9 MB/s.
Figure 9: Buffalo DriveStation USB 3.0 - HD Tune Benchmark Read
The Seagate's (Figure 10) read speed again comes in lower across the board, averaging 82.1 MB/s.
Figure 10: Seagate BlackArmor PS 110 USB 3.0 - HD Tune Benchmark Read
The WD MyBook 3.0 (Figure 11) does much better on read than write, edging out the Buffalo with a 98.7 MB/s average. This difference is so slight, however, that I doubt you'd notice it in real life use.