I have been using HDTach for many years now and always find it is an invaluable benchmark to ascertain potential levels of performance. HD Tach is a low level hardware benchmark for random access read/write storage devices such as hard drives, removable drives (ZIP/JAZZ), flash devices, and RAID arrays. HD Tach uses custom device drivers and other low level Windows interfaces to bypass as many layers of software as possible and get as close to the physical performance of the device possible.
HD Tach measures an average read speed of 377.3 MB/s via the ADATA S511 drive compared to 376.3MB/s from the OCZ Vertex 3 unit. Great results with this benchmark.