Grid computing is a promising concept to increase the efficiency of existing computing systems and to cut down on IT expenses by allowing the dynamic access to computer resources across geographical and organizational bound- aries. These inter-organizational settings require a schedul- ing strategy for flexibly and efficiently matching resource re- quests to idle resources. Market-based mechanisms promise a good fit to grids' strategic and dynamic nature by al- lowing resource requesters to express valuations in addi- tion to technical metrics. The contribution of this paper is twofold: We present a discriminatory pay-as-bid market mechanism by Sanghavi and Hajek [14] and analytically show that it outperforms market-based proportional share ? the currently most prominent grid market mechanism ? with respect to both provider's surplus and allocative efficiency. We further illustrate that this mechanism is not a purely the- oretical construct but that it can be integrated into the Sun N1 Grid Engine, a state-of-the-art grid scheduler.