I have a friend (in college) whose desktop computer is similar: a few circuit boards (motherboard+video, I think) stuck in a bucket of oil, with a radiator+pump

I have a friend (in college) whose desktop computer is similar: a few circuit boards (motherboard+video, I think) stuck in a bucket of oil, with a radiator+pump, monitor, keyboard, and mouse attached. Apparently, it's effective, although it's difficult to suppress the urge to tip the thing over. It's probably not cost-effective as far as power usage, but that's not his concern - he just didn't want fans.