How much RAM can the HP EliteDesk 800 G1 TWR support and what type does it use?

The HP EliteDesk 800 G1 TWR uses four DDR3 DIMM slots for up to 32GB. It has four 240-pin DDR3 DIMM slots running at 1600 MHz, non-ECC, maxing at 32GB. The four-slot layout means you can populate it gradually — start with 8GB, add another stick later, and still have room for more.