Is the WD Raptor or other high performance hard drive worth the extra money over lower performance drives for a NAS? This experiment has shown that the answer, as you might expect, is "it depends". The most interesting finding in this test was that although the D-Link DNS-323 supposedly is set up to take advantage of both SATA 3 Gb/s drives and NCQ, neither appeared to affect performance.
And while the Thecus N5200 isn't set to take advantage of either of these performance-enhancing SATA drive options (at least according to Thecus), it did show performance differences that roughly tracked hard drive performance. But the Thecus is clearly currently in a performance class by itself (for gigabit LAN writes), so it is unlikely that other current NASes would notice the difference among drives.
I personally would probably not pay extra for 16 MB of drive cache. Because, in performance per dollar terms, directly attached drives are going to get you about the same write and 10x the read performance of a WD Raptor in a Thecus 5200.
Two key thoughts I am left with after running this experiment are:
- "How can I get 4 GB of RAM into a NAS?"
- "How much is 8 GB of RAM going to cost for my desktop?"
The best place to put your money to optimize NAS performance is to beef up the RAM on a NAS and each networked client. The $450 price premium of putting 4 or 5 Raptors into a NAS will pay for 8 GB of RAM for one client. It would also pay for an eSATA or Firewire direct-attached disk system, but that brings a different set of tradeoffs. And while you usually can't upgrade a NAS' RAM, you can use our NAS Feature Charts to check out the processor and RAM used on the products you're interested in.
I understand this is a "chicken" position, but it looks like the current state of the art in NAS performance follows the first 3 laws of finance: get the cache, get the cache, get the cache.