peltiers are rarely cooled with just a heatsink, they usually use watercooling loops to keep the hot sides cool. peltiers are very risky becaue if they fail, they will insulate your cpu causing it to fry within seconds. at least with a watercooling setup, if a pump fails the water temperature will climb a little slower then a peltier failing. if i were to use peltiers to keep my system cool id use them as a cooling device to cool the water itself. swiftech has a waterchiller that uses 2x227watt peltiers but it suggests that you use 2 seperate watercooling units just to cool the chiller, so that would make 3 seperate water cooling loops in you system, more work/trouble/risk than im willing to go through. if your looking for low temps your better (and safer) off doing a DIY watercooling or maybe an evaporative water cooling setup.
that a low power peltier, it will cool to sub-ambient temps but dont expect anything great. i have a 70W pelt and it can cool down to low 50F, i wouldnt expect this this to get much lower than 60F. what kind of heatsink are you running there now? if your running a stock intel cooler i dont see the problem in stick with that. its quiet and its a decent cooler, i was overclocking my 2.4 to 3.2 on the stock cooler before going liquid. if you running at stock speeds im pretty sure theres 1U server heatsinks incase you need something very low profile.
1) these peltiers generate ALOT of heat. i dont think you know how much heat these put out. i had a 70w like i said before that i was trying to use with a swiftech mcx370 hsf, it was a huge heatsink with a 1/2" copperplate and a 6800rpm fan on it and that was was barely enough.
2) power is a problem, peltiers draw alot of power and many people who run peltiers use seperate power supplies just to power the peltier unit. i highly doubt the psu you have in that case will be able to run a 80w, maybe a 50w but it would be streching it. whats the info on your psu, whats the wattage and how much amperage is there on the +12 and +5 rails?
I could use a DC-DC PSU that I have just for the peltier. And think that the wattage does refer to the heat given off. Plus the idea of having a peltier is that the cold side is always cold. No matter how hot the air is around it. So even if my Heatsinc gets up to 70C the my processor is still being cooled. That's how they're supposed to work anyways.
Firstly, the peltier (cold side) is not ALWAYS cold unless the hot side is cooled properly. If the heatsink you are using is not dissipating the heat then where would it go? obviously back to the processor. Secondly, a heatsink that is rated OK for a 3.4 will not work as good for a peltier cooled 3.4 because the heat output is not the same. The last peltier i had the heat output was 1.5 times the processor output.
That will tell you all you need to know about insulation. Get some Dielectric grease and coat it all around and in the socket pin holes, and on the back of the motherboard. Its all explained... good luck