I've had CPU cooling fans on every computer I ever owned. Not sure why I waited so long to add them to our beloved c64! Even the colour scheme is perfect. :
MOS 8500 (CPU)
It's Real: A Brand New 1980s Commodore 64 Clone! EVO 64 + CIA + CPU - YouTube
The PLAdvanced+ – breadbox64.com
Vasyl New Hardware for C64 – Retro Hardware
CSG 8500 CPU for the Commodore 64 (New Old Stock) - Retro 8bit Shop
Super CPU 64 - a look inside at the Electronics - Commodore 64
MJK's Commodore Hardware Overview: Commodore 64
Commodore 64x - Wikipedia
Commodore 64 CPU Speed up Cartridges - The History, CMD Super CPU 64/128, Turbo Master CPU C64, Flash 8 , Turbo Process,
CSDb] - TDC-L (D1) 2/4Mhz C64 Accelerator by Kisiel (2011)
Commodore 64 Central Processing Unit (CPU) Replacement - iFixit Repair Guide
Turbo Master CPU | CommodoreServer.com
Commodore 64 - Wikipedia
Commodore 64 - Wikipedia
MJK's Commodore Hardware Overview: Commodore 64
SuperCPU - C64-Wiki
Commodore 64 Accelerator
Commodore 64 Central Processing Unit (CPU) Replacement - iFixit Repair Guide
Commodore 64: Everything You Need To Know - History-Computer