Conclusion: Adaptec Ahead At Heavy Loads
Our benchmarks prove that the two test candidates have similarly high performance levels. While the LSI 20320R has a very slight lead in processing short queries, the Adaptec 39320D-R strikes back during frequent queries over many blocks (queue depth of 64 and more). However, what comes into question is the extent to which these results can say anything conclusive about performance under daily conditions.
For one thing, it has to be said that the differences in most of the benchmarks are so small that, under a small load, they would never bear any significance.
Also, Adaptec shows very clearly that its controller can handle large quantities of data better: if a multitude of queries with high queue depths is directed to the controller, then Adaptec can in fact take a considerable lead and process the queries faster. In other words, under a high load, a file server with Adaptec's 39320D-R can work faster with multiple hard drives simultaneously.
Still, it is a bit awkward to judge a controller as particularly good or bad based on test results, because the number of possible benchmark configurations for special applications is simply too high. In this test, the LSI controller attains maximum I/O performance with one and four successive I/Os per drive, taking a small lead only. If there are multiple I/Os in succession, then Adaptec takes the lead.
Therefore, we recommend the following: if maximum performance is not required, then both of these host adapters do the job quickly and reliably; here, it would be senseless to point out their differences. Price and included accessories should therefore play the most important roll - Adaptec can clearly claim the latter to its advantage, since an Ultra320 cable is included, which can be used for up to four drives. A five-year warranty is offered by both manufacturers.
As long as the host adapter is required for performance-critical applications, then you should take the more circuitous route and put the test candidates (regardless whether it's Adaptec, LSI or others) through an extensive test that corresponds to the configuration that you require. This is the surest way to find out which adapter best fits your needs.
