Benchmark: CrystalDiskMark
CrystalDiskMark uses incompressible data that puts the SandForce processor at a disadvantage - it works best when its built-in DuraWrite technology can compress data on the fly. This, therefore, is a worst-case scenario.
The OCZ Synapse and Corsair Accelerator are closely matched, and while both struggle to compete with standalone SSDs, they're considerably faster than the hard-disk-only configuration.