IOMeter notes
We haven't used IOMeter for a while, so I'll quickly refresh a few key things you should know. IOMeter is an open-source disk benchmarking tool designed to simulate real-world workloads. The benchmark comes with pre-programmed access patterns for file and web servers, and we're using some workstation and database access patterns defined by StorageReview.com. We'll be looking at transaction rates, throughput, response times, and CPU utilization for the different access patterns for each card and each array configuration.

IOMeter - Transaction rate - RAID 1

Though different access patterns produce slightly different transaction rate results, general trends persist throughout with RAID 1. At the bottom of the performance pile overall (provided you don't take into account single-drive configurations) is Adaptec's 2400A, which doesn't really manage to gain any performance advantage over any other RAID 1 configuration. Depending on which access pattern and load level you look at, the other three cards are fairly evenly matched. HighPoint's RocketRAID 133 turns in more of a streaky performance, but it's right up near the top at our highest load size setting.