Results: I/O Performance RAID 5
RAID 5 is probably the most important mode. Adaptec is fastest in our RAID 5 benchmark testing with 16 hard drives, while Promise follows close behind. Areca hits a bottleneck once command queues of eight pending commands are reached—beyond this point, performance will not increase further. However, a broken hard drive drops Promise to the last position, as the performance impact on I/O performance is much larger than is the case with Adaptec or Areca.