All testing was done using iozone running on the "New NAS Test Bed" machine (Core 2 Duo E4400, 512 MB) that I have been using for testing in the Fast NAS series. I ran all tests using Vista SP1, since it seems to give tested NASes a bit of a speed boost over XP SP2.
Figure 1 shows write results for as apples-to-apples comparison as I could get. The more rapid falloff from cached performance for the 4100PRO is due to its smaller RAM size. But once both products get beyond caching effects, the Atom machine has about a 20% advantage. Both NASes, however, deliver RAID 0 write performance in the 20 MB/s range, which is above the 100 Mbps LAN theoretical line, but significantly below the 1000 Mbps PCI actual line.
Figure 1: Atom vs. Geode - Write
Figure 2 shows read results, which show that the products have swapped lead positions for cached performance. The Geode-powered N4100PRO stays up above the 68 MB/s line until it hits its 256 MB RAM size, while the Atom NAS maxes out at around 55 MB/s. Once both products go past their RAM size, however, read speeds are virtually identical at around 31 MB/s.
Figure 2: Atom vs. Geode - Read
Since I had everything set up, I thought I'd vary a few hardware elements to see how they would effect performance. For the Atom NAS I boosted RAM size to 2 GB, the same configuration I used when I ran it with FreeNAS and Ubuntu Server. For the Thecus, I decided to add a third drive to the RAID 0 array.
Figures 3 and 4 show the new results added to the original, neither of which seems to make much of a difference in performance.
Figure 3: Atom vs. Geode w/ hardware variations - Write
The third drive in the N4100PRO flattens the cached to non-cached line slope only a bit, as does the additional RAM in the Atom NAS. But once the non-cached filesizes are hit, there is no difference from the hardware changes.
Figure 4: Atom vs. Geode w/ hardware variations - Read
As I noted earlier, I decided to use Openfiler 2.3 to run the Atom NAS data. But since I had comparable data from my Ubuntu tests, I thought I'd throw that into the comparison, too, shown in Figures 5 and 6.
Figure 5: Atom vs. Geode w/ hardware variations and Ubuntu - Write
I was quite surprised to see the difference that Ubuntu made in write performance and it even managed to raise read performance a bit (at the expense of eliminating a speed boost at smaller file sizes. I used ext3 and 64K stripe sizes when formatting the RAID 0 array in both cases. So I can only attribute the difference in performance to something else in the Ubuntu Server distro.