Samsung outs new firmware ‘DXM05B0Q’ for 840 Pro and ‘DXT08B0Q’ for 840 Series SSDs. The new firmware enables DAS (Direct Attached Storage) function by default for 840 Pro, whereas it improves 840 for ‘specific’ uses.
DAS units are used as storage systems directly to the system or a workstation without any network system in the middle, rather using HBAs like LSI’s RAID adapter. The number of user were being affected when using multiple Samsung 840 Pro connector through any of the LSI controller RAID cards they have, irrespective of the RAID preset.
According to Serve the home forum users there is a problem when the SSDs are connected to the HBAs, switched to HBA mode and using software RAID, the write speeds fall about 300 Mbps for the entire SSD array. it seems that it has made an improvement, specifically for RAID 5, although its been added at the same time that its not yet confirmed if its working the way it should.
You can download the newer drivers from here.