The barebone comes with a 2.5" 320GB SATA HDD installed. Manufactured by Samsung, it spins at 5400rpm and has 8MB of cache. The HDD model is part of Samsung's SpinPoint M6 series of HDDs:

The hard disk drive was already partitioned:

Everest Disk Benchmark gave us some information about the supported reading speeds:

The linear reading tests starts at 68MB/sec and ends at 35MB/sec - a typical performance for a 2.5" 5400rpm HDD. The average read access time reported is 18ms, which is rather high.

The HD TachRW software seems to agree giving an average of 56.4MB/se reading and 18ms random access time.