Traders use 2d Nvidia NVS cards that are fanless. You do not need a 3d card as they are overkill and run hot so need a noisy fan to cool. Fanless nvidia nvs 295 dual cards can be had on ebay for $10-40. A fanless quad NVS 440 is $25-$100. They do an octa (8) head as well.
That's true for 2008, not true for 2018.
Modern cards newer than GTX960 have dual fans but the fans don't spin in 2D applications. Even if they spin, they're close to silent. They don't run hot either, many mid-range models are close to CPU temps. I'm saying this while living in a tropical and humid climate.