Now I will try to sum everything up. Talking about inexpensive RAID controllers in general, they can be an optimal choice if you can’t buy a more expensive model due to financial constraints or because you just don’t need such a model. There is one important note about Adaptec’s controllers, though. They are not good for RAID0 if you need a high speed of sequential reading/writing rather than a high number of operations per second.
As for the specific models, the ASR-3405 is the best controller in today’s tests. This new-series model is generally far faster than its predecessors. Moreover, it is based on the PCI-E 4x rather than PCI-X interface and supports SAS drives. This controller is good with RAID5. Although not without problems such as the lack of performance scalability at long queue depths, low speed at multithreaded load and at random-read reading from RAID0, it is overall worth its price.
The AAR-1430SA, a very inexpensive controller with a PCI-E 4x interface, may suit people who have a limited budget but want to increase disk performance in terms of read operations per second by means of RAID0 or increase data reliability by using RAID10. This controller is almost everywhere better than the AAR-1420SA, the developer’s previous model with a PCI-X interface.
The AAR-2820SA and ASR-44300 are generally slower than the ASR-3405, being only good in one or two tests. Particularly, the former was good at multithreaded reading and at copying files while the latter was good at random reading from RAID10.
And a piece of general advice: if high disk performance is indeed important for you, you should not save on the RAID controller. In any case, make sure it is going to do well under your type of load.