Towers are the biggest Desktop PC form factor, with a height normally of 60cm (24") or more. They can accommodate more internal drive bays and have the highest capacity for PCI expansion. The best selling HP EliteDesk 800 G3 Tower supports 7th Gen Intel Core technology, is capable of taking up to 64GB DDR4 Unbuffered RAM, M.2 NVMe SSD and has 4 x PCIe expansion slots.