Quote:
high power usage and high power dissipation are the biggest problems related to peltier cooling. In the days of first-generation Pentium CPUs, readymade peltier/heatsink combinations were widely available, which could be installed and used just like a regular heatsink.
For today's CPUs having a power dissipation of over 100W, building a Peltier CPU cooler using just a peltier element and a heatsink is quite a challenge, and ready-made peltier coolers are scarce and expensive. With such coolers, over 200W of heat may be dissipated inside the case. For modern CPUs, it is better to combine peltier elements with watercooling. In any case, the resulting cooling system will be expensive to run, due to its high power usage, and not very eco-friendly. The large power dissipation will require powerful (and thus loud) fans.
Also, keep in mind that if the cooling of the peltier element fails (e.g. fan failure or pump failure in case of watercooling), the results will be more disasterous that if a conventional cooling system fails. Even if your CPU has a thermal protection that will cause it to shut down if the temperature gets too high, the peltier element may still kill it by continueing to heat it up long after it has shut itself down.