We should first try to determine which version of the R810 you have. Since you have the E7-4870, I would think you have the R810II (roman numeral 2), but we should be sure. See page 3 to determine which version your R810 is: https://downloads.dell.com/manuals/all-products/esuprt_ser_stor_net/esuprt_poweredge/poweredge-r810_user%27s%20guide4_en-us.pdf

The top of page 6 says if your system is not an R810II, you should update the CPLD, Bios (you did already) and idrac. I would recommend updating them if they arent already updated. 
CPLD: https://www.dell.com/support/home/us/en/19/drivers/driversdetails?driverid=3gvk7&oscode=ws8r2&productcode=poweredge-r810

IDrac:https://www.dell.com/support/home/us/en/19/drivers/driversdetails?driverid=9gjyw&oscode=ws8r2&productcode=poweredge-r810
the idrac update can be uncooperative at times depending on the currently installed version. If the windows 32bit .exe file on the site gives you problems, download the FW_IMG.exe version, extract the files and use the firmimg.d6 file via the idrac gui update method. 

Lastly, I googled the model of the Samsung dimm, and it shows that the dimm is low voltage capable. This made me wonder about page 7 of the doc in the first link. The Memory Operating Voltage setting might help, and I would try one of the other settings if its already set to Auto. On page 8, the processor settings section, try disabling the C States in the bios as well. 
I'm not sure if you tried just the Samsung dimms to see how they behave by themselves, just a thought. Let us know how it goes.

#Iwork4Dell

Thank you for this guidance.

You are correct, I have the R810II machines.

I updated the CPLD to 1.5.0. I updated the iDRAC to 2.90. The BIOS was already on version 2.11.0.  I tried removing the original sixteen 4GB DIMMs so that the only DIMMs installed were the sixteen 8GB Samsung DIMMs.  I tried disabling the C-states in the BIOS. I am still getting the same unsupported DIMM errors. The BIOS doesn't give me the option to change the voltage when the 4GB and 8GB DIMMs are both installed, the only option is Auto.  With only the 8GB Samsung DIMMs installed, I still don't have an option to change the memory voltage. 

Is there anything else I can try?

Thanks again!

That is what I ended up doing. In hindsight, I should have tested the Samsung DIMMs for a few days with prime95 to see if there were any errors before sending the DIMMs back.

Thanks again,

David