Most video cards use fans to keep the GPU and circuit boards running nice and cool. If you have multiple video cards in your PC or high-end cards that generate lots of heat, the noise from the fan can drive you crazy.
Some video cards are offered in passively cooled editions to help reduce noise in the environment around you. Club 3D has unveiled just such a card called the ATI Radeon HD5550 Noiseless Edition. The video card uses the PCI-E 2.1 slot and has no fans. The GPU is clocked at 550MHz and the card uses 512MB of GDDR3 RAM.
The memory is clocked at 800MHz and the card has memory bandwidth of 128-bit and 320 stream processors. Club 3D uses a dual heat pipe passive cooler to keep the card running cool despite lacking fans.