The coupled diffusion equations recently proposed for concentrated hard-sphere suspensions are numerically solved to investigate the dynamics of density fluctuations around time-dependent nonequilibrium ͑spatially inhomogeneous͒ states. As the volume fraction of spheres approaches the critical value g from below, the self-intermediate scattering function F S (k,t) is shown to obey two different slow relaxations whose time scales t ␤ and t ␣ diverge as the separation parameter ϭ(Ϫ g )/ g

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... es zero: t ␤ ϳ͉͉ Ϫ␤ and t ␣ ϳ͉͉ Ϫ␣ , where g ϭ(4/3) 3 /(7 ln3Ϫ8 ln2ϩ2). Thus, the importance of nonequilibrium effects on slow dynamics is stressed from a unifying viewpoint. ͓S1063-651X͑97͒50601-5͔