adequate radiator?
 

Let's say I never want to cool with a peltier, but I do want to overclock. Are those 4x4 radiators (Hayden something-or-other) adequate, or is a heater core really necessary?

Thanks!

If you mean those small ones like the tranny kinda ones then maybe, it will not suffice much of an over-clock at all because of its design.( not sure the specific flaws, im no engineer or anything, but its design/materials cause it to decrease in performence.)If you want to get a really good OC and still get low temps then you should go with the Big Mamma from caseetc or the aquacoil.

They are pretty good for modest load, but a massively overclocked Athlon might give one trouble. To be honest I'm not sure how they perform, but I'd assume they have a fraction of the heat drop of a Big Mama. I'd try and get something a little larger (even if you don't need that kind of performance, a better radiator means a quieter radiator fan). Also AFAIK they are usally Aluminium, which is not recommended in a system which contains copper (nearly all waterblocks are copper).