Yes, a Xeon 2620v3 could work with DDR3 memory.
Yes, a Xeon 2620v3 could work with DDR3 memory.
I discovered a Chinese x99 board with DDR3 dimms and a 2011v3 socket. I'm checking if using a DDR3 processor and an Xeon such as the 2620v3 would function properly. The Xeon supports DDR4 speeds up to 1866, so DDR3 should be compatible.