The following graph shows the overall performance of the NAS on all tests we conducted using our custom-made software.
The N5550 performed decently overall. However, we expected transfer speeds to be a little higher since all other NAS boxes with Atom CPUs tested so far registered higher speeds. The lower-clocked D2550 CPU definitely plays its role here, but this is one of the few NAS servers—and the only one among those we have tested so far—that also comes with 2 GB of DDR3 RAM installed, which, as it seems, doesn't help much with network throughput. Finally, the external disk we hooked up was really slow with NTFS, so you had better stick to EXT4.
Now, let's check the performance of the N5550 versus other NAS devices.