How to enable hardware based encryption on Samsung 850 Pro

As the "someone" working on "msed", it now has the ability enable the OPAL locking, write a PBA to an OPAL 2.0 drive and chain-load the real OS after unlocking the drive on bios based motherboards. No special motherboard support is needed. Yes, it is still early in it's development cycle and it currently does not support sleep to ram as that requires OS hooks.

Depends on what you mean by "get this to work". That drive support OPAL 2.0, which allows various software managed encryption schemes to use hardware accelerated encryption. It also allows for pre-boot authentication (PBA) for encryption, such as BIOS/EFI schemes. If you want to use PBA (ie a password/pin at the BIOS/EFI) then you'll have to switch to a motherboard that supports it (I couldn't say which as I don't use PBA, I use BitLocker, which I highly recommend in Windows environments).

TL;DR If you're running Windows, use BitLocker, it will automatically use the hardware acceleration.

Edit:
As of April 2014, OPAL is not supported by Linux. There was someone working on "msed", but it wasn't finished or production worthy. I don't know the current status or future of OPAL support in Linux.

Edit 2:
There are also various UEFI products that can manage OPAL compatible drives allowing for a variety of PBAs if your BIOS/EFI doesn't support it directly. The only one I've vaguely familiar with allows companies to setup an authentication servers for PBA over the Internet. It might work with local credentials as well, I'm not sure. It's also very expensive. Food for thought if nothing else.

TexasDex is correct. Your motherboard BIOS must support an ATA Password option (this is distinct and in addition to the BIOS password). Now the interesting bit . . . no one mentions this feature. Not in mobo reviews, comparisons, and certainly not in the advertisements and listings of the mobo manufacturers. Why not? Millions upon millions of Samsung EVO and Intel SSDs are ready to have ultrafast and ultrasecure hardware encryption enabled, all they need is a BIOS with ATA Password support.

The only answer I could find is that Mobo makers are afraid a few noobs will forget their passwords, and since this encryption is so reliable, no one AT ALL will be able to help.

I had an ASRock Extreme6 mobo, and thinking it was the latest and greatest, of course it would have this feature. Not. However, I wrote to ASRock in Taiwan and in a week they emailed me the 1.70B version of their BIOS with an ATA Password option. However, it's still not available on their website, you have to ASK for it (?!). This may be the case with your mobo makers as well.