Single-slot vs dual-slot GPU

A single-slot GPU is a card thin enough to occupy one expansion slot opening on the back of a chassis. A dual-slot GPU occupies two openings. Slot count measures thickness only, and makers list height and length separately. It also sets how many cards fit side by side on one board.

NVIDIA lists the RTX PRO 4000 Blackwell as a single-slot card at 145 W. The RTX PRO 6000 Blackwell Max-Q Workstation Edition is dual-slot at 300 W, and so is the 600 W Workstation Edition. Power does not set width alone, since the RTX PRO 4000 Blackwell SFF Edition is dual-slot at 70 W. Some GeForce cards run wider. The GeForce RTX 4090 Founders Edition is a 3-slot card, 61 mm thick, rated at 450 W. Slot count also overstates capacity. Supermicro's SYS-741GE-TNRT tower has seven PCIe 5.0 x16 slots but lists room for four double-width GPUs.

Count slot widths, not slots. For four or more GPUs in one chassis, choose single-slot or dual-slot cards, then confirm the board's double-width slot count.

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Last verified October 7, 2026.