Sorry I misread your initial post as 2X8GB not 8X2GB. In that case. 2X16GB is the best option to get to 32GB. 
Dear all, we currently own a Dell R610 (dual Xeon E5620) with a total of 16GB RAM consisting of 8 x 2GB. We are planning to double the memory to 32 GB. What would be the best RAM configuration? Taking all the existing RAM out and replacing it with 2x 16GB? (one module in slot A1 and the other one in slot B1). Should we go for low-voltage RAM, e.g. Kingston ValueRAM KVR13LR9D4/16 Or do you have any better suggestion? Thanks in advance!  Best regards Oliver
Dell R610 RAM configuration