  We study the relation between exactly marginal deformations in a large class
of N=1 superconformal quiver gauge theories described by brane tilings and the
degrees of freedom in the corresponding 5-brane systems. We show, with the help
of NSVZ exact beta functions, that there are generically d-1 complex exactly
marginal deformations of a gauge theory, where d is the perimeter of the
corresponding n it, and the other two, the diagonal gauge coupling and a
beta-like deformation, as background supergravity fields.toric diagram. We
identify d-3 complex marginal deformations as deformations of the brane system
and the Wilson lines on it, and the other two, the diagonal gauge coupling and
a beta-like deformation, as background supergravity fields.
