but 100$ for a cpu heatsink?? gtfo. But im curious how well would an all copper heatsink actually perform?
They perform very well. The Thermalright TRUE copper Ultra-120 eXtreme is a very good heatsink once you put some time and effort into lapping the base and buying a good fan for it. They are notorious for having uneven bases. But TRUEthfully, I really don't think it's worth the $100+ you're going to have to spend for the thing when you can get coolers that work just as well for much, much less.