The HP EliteDesk 800 G4 TWR's max RAM depends on which motherboard revision you have

The HP EliteDesk 800 G4 TWR’s max RAM depends on which motherboard revision you have

Here’s a quirk: the G4 TWR’s memory ceiling isn’t the same across all units. One revision tops out at 64GB with two 32GB DIMMs, while another caps at 32GB with four 8GB sticks. Both run DDR4-2666 non-ECC, so the actual limit depends on which motherboard revision HP put in your chassis. Check yours before ordering upgrades.