- This problem is happening independent of the OS. (With a seeming preference for Windows OSs)
- The disks are not showing obvious filesystem corruption.
- The disks are not showing obvious physical corruption via SMART.
The major component that is left is the RAID controller itself, specifically it's interaction with the physical hard drives. There could be a problem with timeout mismatches between the hard drives and the controller. When I see disks as larg as 2TB, I am immediately suspicious that they are a consumer grade drive not intended to be used with enterprise disk controllers. Confirm that your disks are designed with the intention of being used in a hardware RAID array.
Next, confirm the operation of your RAID card. You mention that the chip is Sli, however Sli to the best of my knowledge does not manufacture and sell RAID cards, but rather makes the chips that other manufactures purchase and use for their own cards. Those manufacturers then provide their own drivers and support. Find the actual manufacturer of your RAID card as a whole, not just the chip manufacturer.
Look for logs files and alerts within the RAID card itself. Seek information from it concerning timeout limits. It's possible that it is holding logs that are not being directly reported to the OS unless the proper drivers have been installed.