In both Figures 2 and 3, horizontal lines are provided to provide a frame of reference on the NAS/Hard-disk speeds. The bottom line is black and represents the speed of 100 Mbps Ethernet. The second line from the bottom is red and represents the speed of Firewire 400 (to give a comparison for directly attached storage throuput). The top line is orange and represents the speed of 1000 Mbps Ethernet. Including the gigabit Ethernet line made the separations between lines meaningful in judging the relative speed differences.
Each figure has two groups of four lines: Thecus 5200 was faster and its results are on top, D-Link 323 is on bottom. Each line within a group represents one hard drive's performance averaged over four trials.