Yes, you need to reapply thermal paste because default from the factory is so-so. But are you skilled enough to do that? If you decide to try then buy thermal grizzly Kryonaut or Gelid GC-Extreme. Both (especially second) are the best if you don't use liquid metal. If it is too expensive for you then pick up MX-4.
Ok I'll try the thermal paste first. Is Innovative Cooling Diamond better then the Kryonaut or GELID? What about the Coolaboratory?