Looking to buy a USB powered laptop cooler, found two decent ones on sale, one uses 2x 92x92x25mm fans, the other uses 4x 60x60x10 fans.
Both are rated at 5volts:
2x92's: 1700-1900rpm, 18-20dba
4x60's: 1900-2600rpm, <24dba, quoted at 40cfm
I don't know how much air the 92's move, and...