Pros: * Super easy upgrade from an Adaptec 6405 to this. Just plug the card in, attach the internal cable (once you have it), attach the cables to your drives in whatever order, the card determines what the correct order is automatically and asks you to confirm. * Twice the cache of the 6405

Cons: * Doesn't include the cable that's needed. You local electronics store most likely doesn't have the cable for sale (mine didn't) so you'll probably want to grab it from Newegg while you're here. * There seems to be some kind of bug with the card, or maybe it's my system, but when I do a soft reset or soft reboot, the card doesn't re-detect the drives. Never had that problem with the 6405.

Overall Review: The internal connector is SFF-8643 and my drives are SFF-8482, so the cable I opted for is "ADAPTEC 2280100-R 0.8M INT MINI 4SAS HD SFF-8643 TO 4XSAS SFF-8482 FAN-OUT CABLE". Adaptec has a cable chart on their site somewhere.

Pros: True hardware based RAID controller Supports RAID 5 and 6 (as well as other modes) Supports UEFI (GPT) Fast processor Seems very stable

Cons: Pricey Be aware of air circulation requirements

Overall Review: RAID arrays are one approach to minimizing data loss potential. There are other less expensive ways (backing up important data to a flash drive, for instance). Further, in today's environment (ransomware, etc.), backups are absolutely essential. Performance: Running four (4) Toshiba 2TB P300 drives in a RAID 6 array (resulting in about 4TB usable storage), the real read speed for the array is about 250MB/s. This is near theoretical, as a 7200 rpm drive can spit out between 80 - 160 MBs continuous maximum, and with 4 drives in a RAID 6 array the limit would be double the single drive speed. Note that the apparent read speed can appear to be much higher if tests are made with a test file at or under the 8405 buffer size (1GB). Such results are unfortunately largely meaningless. I chose RAID 6 because of the extra insurance against a failure during rebuild. Both RAID 5 and RAID 6 require substantial time (many hours) to rebuild. If a second drive gives up the ghost during rebuild, you would be lost with RAID 5. Additionally, I chose hardware RAID because I am running a dual boot system (Windows & Linux). Unfortunately, there is no software ("fake") RAID for levels 5 or 6 that is compatible with both Windows and Linux. I bought the drives for this computer over a year ago, but upgraded to the 8405 only a month or so ago. If I were building a computer today, I would strongly consider incorporating an SSD in the system. One caution: check the specs on your motherboard carefully regarding the bit width of your PCIe "x 8" or "x 16" slot. I cannot overemphasize this. It is within the PCI Express specification to have a physical 16 bit slot, but have only, for example, 2 bit support. I got bit on that, and had to move the 8405 to another slot before it would behave properly.