The AAR-2820SA is a more serious device and it even looks such. You can see a XOR processor and onboard memory on it.
I will test a version of this controller with 256 megabytes of buffer memory but there exists a 128MB version, too. Oddly enough, the manufacturer doesn’t mention anywhere at his website what type and how much of memory this RAID controller uses. The marking on the chips is barely readable. Judging by the 128MB model, there are four DDR modules with a frequency within 200-333MHz.
The controller’s interface is 64-bit/133MHz PCI-X. It supports up to eight hard disk drives with SATA interfaces (NCQ and 3Gbps data-transfer rate). The controller is based on the Adaptec AIC-8210 chip and supports a wider selection of RAID types: 0, 1, 10, JBOD, 5, and 50. As opposed to the previous models, this one supports a battery for the buffer memory and all the capabilities offered by the Adaptec Advanced Data Protection Suite, namely:
- RAID1E arrays (a mix of RAID0 and RAID1, it allows to make a mirror out of an odd number of HDDs)
- RAID5E arrays (RAID5 with an integrated spare disk)
- RAID6 and RAID60 (similar to RAID5 and RAID50 but the checksums are stored on two rather than one disk)
- Automatic copying of data from the replacement disk to the new one installed instead of the failed disk. This technology helps keep the replacement disks always in the same bays of the case which may be convenient.