Let (R, m) be a commutative Noetherian local ring, a be a proper ideal of R and M be an R-complex in D(R). We prove that if, then idRRΓa(M ) = idRM (respectively, fdRRΓa(M ) = fdRM ). Next, it is proved that the right derived section functor of a complex M ∈ D❁(R) (R is not necessarily local) can be computed via a genuine left-bounded complex G ≃ M of Gorenstein injective modules. We show that if R has a dualizing complex and M is an R-complex in D f (R), then GfdRRΓa(M ) = GfdRM and GidRRΓa(M ) = GidRM . Also, we show that if M is a relative Cohen-Macaulay R-module with respect to a (respectively, Cohen-Macaulay R-module of dimension n), then GfdRH ht M a a (M ) = GfdRM + n (respectively, GidRH n m (M ) = GidRM − n). The above results generalize some known results and provide characterizations of Gorenstein rings.