We purchased an OptiPlex 7050 Tower running Windows 10 Pro for a customer with two 1TB 2.5" drives in RAID1 from the factory.  When I started prepping the machine for installation, I installed updates (Dell and Windows) and changed the RAID caching settings to disable "Write-cache buffer flushing" and then set Cache mode to Write Back.  After doing that, the computer installed Windows updates fine but started locking up when copying large amounts of data.  I started testing and found that if I had the cache mode set to Write Back and then tried to copy 2GB+ of files, the Windows copy dialog would go to about 10-20% and then just drop to 0.  At that point, nothing that accessed the hard drives would work and I'd have to power off the computer.

If I change the cache mode to Write Through, there are no issues with locking up.  I checked and there was no update from Dell for the Intel RST drivers (15.7.xxx) but there was an updated version from Intel (15.9.xxx) and so I updated but have the same results.  Anyone else having issues like this?  I've run into it on two different OptiPlex 7050 towers.