Access Time And I/O Performance
Surprisingly, the WD20EADS is even quicker than the Barracuda 7200.12, which works at faster rotation speeds. Access time quicker than 15 ms can be considered fast, while anything above 20 ms would be really slow. Hard drives selected to run operating systems and applications at fast speeds should offer quick access times, while storage drives can be slower, as you typically won’t notice the difference.
The fastest and slowest drives in read access times are also the fastest ones in the write access tests.
As mentioned before, the new 2 TB WD20EADS does very well in access and I/O performance. Seagate obviously hasn’t optimized its new Barracuda 7200.12 for these workloads.