Xeon-opteron For Renderfarm

[radioVOY]

i have a two dual xeon 2.4 with 2 gigs, 300gigs scsi HD, and quadro 4 780xgl

and im starting a renderfarm, just 4 units, but i read about on this forums and looks to be not compatible xeon with opteron on the same renderfarm. is this true????

 

another question:

if thats true what will be better dual xeon or dual core opteron???

 

and:

 

can anyone submit a tutorial for build the renderfarm??? i got some knowledge about networks.

 

i want to decide between dual xeon emt64 3.6ghz or dual core opteron 246.