Boss, mag-basa ka nag konti about DNS postive/negative TTL caching para mas maunawaan mo.
Halimbawa, nag-query yung machine mo for the domain 'targetdomain.com' against sa configured resolver which can be google's, your ISP's, openDNS, or whoever. Sa tingin mo ba yung respons, be it positive (domain found with an IP associated to it) or negative (NX reply, no such domain) ay forever sa cache? Ang sagot hindi. Because it depends on: a) the TTL set by the domain owner; b) if the receiving machine respects that or not. Though 98% of the time, it does.
In short, DNS resolver does affect the browsing (and other internet activities) speed and experience.