I covered the features fairly extensively in the original NSA325 review and Tim covered the updates in his review of the NSA325 v2. So hit those reviews if you want details on the NSA320's features. Here are a few screenshots of the UI to give you a flavor of it.
ZyXEL NSA320 home page
ZyXEL has an online eumulator if you want to explore the user interface and features further.
ZyXEL NSA320 admin home page
The NSA320 was tested with V4.62(AFO.0)C0 firmware using our standard NAS test process. In reviewing the NSA320, two questions came to mind: How does the performance compare to the identically-featured $189 NSA325 v2 or in other words, how much performance am I going to give up in order to save $89? The second question is how does the NSA320 compare to the identically-priced $100 TRENDnet TN-200?
There are two ways to drill down on the performance to get the answer. First I looked at the File Copy Write and Read performance for both RAID 0 and RAID 1. The first two charts below show performance comparisons for all two-bay SoC-1 processor-based NAS products.
RAID 0 File Copy Read and Write performance for 2 bay SoC-1 NASs
Looking at File Copy Write performance, you can see that the two ZyXEL NASes are running neck-and-neck with the NSA325 v2 having an insignificant edge (52.3 MB/s vs. 53.0 MB/s) over the NSA320. However, the NSA320 was 15% faster for File Copy Writes than the TRENDnet TN-200.
File Copy Read performance is a different story. The NSA325 v2 was 28% faster than the NSA320 (86.9 MB/s vs. 67.9 MB/s). The TRENDnet TN-200 was near the bottom of the charts at 55 MB/s.
If you are planning to use your NAS in RAID 1 mode (mirrored drives) for data redundancy, the next chart will be of particular interest to you. Where there was no virtually no difference in write performance between the two ZyXELs for RAID 0, for RAID 1, the NSA320 takes a performance hit compared to its more expensive sibling.
The NSA325 v2 was 31% faster than the NSA320. (52.7 MB/s vs. 44.2 MB/s) for RAID 1 File Copy Write. But the NSA320 held about a 10% advantage over the TRENDnet TN-200 (44.2 MB/s vs. 40.1 MB/s) for the same test.
RAID 1 File Copy Read and Write performance for 2 bay SoC-1 NASs
For RAID 1 File Copy Read, we saw a similar spread in performance. The NSA325 v2 was faster than either the NSA320 or the TN-200. The NSA325 v2 was 29% faster than the NSA320 (86.5 MB/s vs. 67.2 MB/s) and the NSA320 held a 38% advantage over the TRENDnet TN-200.
Using these two charts, you can make your own comparisons. If you want to generate your own charts, you can also sort the results by price so that you can see what your additional dollars buy (or don't buy) you.
The second way to evaluate performance is to compare all of the benchmark tests side-by-side. While you can't generate charts like the one below automatically, through the magic of an image editor, I was able to cut and paste together (using 11 layers) the chart below.
Comparative benchmarks for the ZyXEL NSA325 v2, NSA320 and the TRENDnet TN-200
We've covered the File Copy Read and Write comparisons in the two previous charts. In this chart, you can compare the balance of the tests, i.e. NASPT tests and backup tests. In most cases, the story is the same. The NSA325 v2 outperforms, but often, not by too much, the NSA320, and the NSA320 outperforms the TN-200 in all but a couple of tests.
I've highlighted the tests with a red box where the NSA320 outperformed the other two devices. In a few cases, such as the NASPT tests for File Copy to NAS, Content Creation, Office Productivity and HD Playback & record, the NSA320 had a slight edge over the NSA325 v2. It lost that edge, but not by much, for the corresponding NASPT tests using RAID 1.
Both ZyXEL NASes had similar Backup to USB drive performances and both blew away the TRENDnet for backup to an NTFS formatted drive. Of course, only the NSA325 v2 has a USB 3.0 port, and you can really see the performance advantage in the Backup to USB3 tests for all three supported partition types.
The NAS Ranker provides the best way to get a relative performance ranking based on all benchmarks measured. Filtering the ranker for single-core SoC processors and two drives reveals the NSA325 v2, with a Total NAS ranking of #30 for all NAS devices tested, remains in third place behind Buffalo LinkStation 420 and ioSafe's N2, which is a Synology DS213 in a disaster-proofed enclosure.
The NSA320 with a Total NAS ranking of #39 ranks in eigth place for 2 bay SoC-1 NASes. If you sort the results by price, you end up with the chart below. Here, the NSA320 is at the top of the list, significantly beating the TRENDnet TN-200.
NAS Ranker sorted by price for 2 bay SoC-1 NASes
To buy a NAS with a better (lower) Total NAS ranking, you'd have to spend almost 50% more to buy the #36 ranked Buffalo LinkStation 421e or the #30 ranked Buffalo Linkstation 420. Considering the extensive feature set of the NSA320 that matches the features found on its $189 NSA325 v2 sibling, it's a great buy. And, for the same $100, the NSA320 handily beats the TRENDnet TN-200.