It's no secret that hard drives -- with or without RAID -- have long been the weakest link of an enthusiast PC but until somewhat recently flash-based alternatives weren't affordable enough for the masses. In 2009, SSDs including OCZ's original Vertex were fetching $3.00 per gigabyte or about $350 for a 120GB model, quite a bit more than a 2TB hard drive at the time, which were going for as little as $0.06 per gigabyte.

Prices have dropped significantly since then, with high-end SSDs such as the Samsung SSD 840 Evo costing as little as $0.75 per gigabyte for a 120GB version. That's still a serious premium over a disk drive such as the Western Digital Black 3TB, which only costs $0.06 per gigabyte, while 2.5" laptop drives such as the WD Blue 1TB can be had for $0.09 a gig. This discrepancy can make it hard to balance speed and space.