Intensive OGL needs in heterogeneous environment

Hi folks,

In an heterogeneous architecture with UNIX servers and PCs for rendering (working as visualization station) how can I use efficently these PC workstations in order to use all capabilities of their HE graphic cards? Of course the application is running on UNIX server.
Is it something which can be done at the config level, using X servers and GLX clients?
What is the performance impact of having a such config vs. homogeneous config (only UNIX servers with equivalent graphic capabilities)?

Many thanks,