Performance - Competitive
The RAID 1 write comparison is shown in Figure 6, which has a compressed vertical scale due to the WD's high cache boost. But if you look at the table below the plot, you see that the Buffalo is the clear winner. Its throughput is in the high 20 / low 30 MB/s for file sizes 512 MB and above, while the NAS 220 runs around 19 MB/s.
Figure 6: Competitive RAID 1 write comparison - 1000 Mbps LAN
Figure 7 compares the read performances, where, once again, the Buffalo produces the best results, except for a dip at the 512 MB point. But the NAS 220 comes in second, maintaining speeds in the mid 30 MB/s range for the largest file sizes.
Figure 7: Competitive RAID 1 read comparison - 1000 Mbps LAN
Performance - File Copy
A different perspective on performance is provided by the Vista SP1 1000 Mbps RAID 1 file copy write results in Figure 8. The rankings are similar, but the throughput values are different. The TeraStation Duo once again bests the NAS 220, with the WD and Linksys NASes following.
Figure 8: RAID 1 Vista SP1 File Copy Write
Figure 9 shows the 1000 Mbps RAID 1 File Copy read. The Buffalo Duo really jumps to the top of the chart, while the Linksys Media Hub stays at the bottom. The NAS 220 measured 42.6 MB/s, which is better than the iozone averaged results.
Figure 9: RAID 1 Vista SP1 File Copy Read
Use the NAS Charts to further explore performance.
In the BA NAS 440 review, we concluded that its closest competitor was the Buffalo TeraStation III. And in this review, I have to say that a Buffalo NAS is again the closest competition, but this time it's the recently-reviewed TeraStation Duo.
However, the Buffalo TeraStation Duo has the 220 beat in performance, most likely due to is beefier Marvell Feroceon CPU and 512 MB of RAM. The Buffalo Duo also is a more Apple friendly since it can function as an Apple Time Machine store, has dual network ports and downloads Torrents.
On the other hand, Seagate has priced the 220 aggressively at around $400 for 2 TB vs. around $600 for the 2 TB TeraStation Duo. And Seagate offers a 4 TB 220 version for only $700 (MSRP), while Buffalo doesn't even have a 4 TB Duo model. Finally, if NAS-to-NAS backup capability is on your shopping list, the 220 will work with other rsync-based NASes, while Buffalo mainly likes to deal with its own kind.
If all this makes you want a BlackArmor NAS 220, you may have to wait just a bit. Seagate has just started shipping them and they will probably hit the Seagate store first (at list price, of course). But by the end of August, there should be plenty to go around.