Hello

I would not suggest installing that board in an R720XD. 76DKC is a kit for a Compellent storage appliance. The system board used in the kit is an old R720 system board. I'm not sure what other changes have been made to the board, it is likely running a custom BIOS that would not work with an R720. It is also 5 revisions older than 020HJ.

Thanks

Thanks for the answer. So I should try to find only 020HJ? Or any other part number can be suitable for me? Because I found only refurbished motherboards with part number 020HJ. 

Yes, I suggest replacing like for like. We do not sell the system boards retail, all system boards you find for sale should be marked as open box, refurbished, or used. Anything not sold in original retail packaging cannot be sold as new. They are not individually packaged for retail sale.

Look for one of the Dell part numbers listed below on eBay and purchase through a reputable reseller.