multi mode timing optimisation

Hello All, I am used pks tool from candence very well and now using soc encounter. I think lot of people faced problems in timing closure with different modes in design. Because if we meet timing in one mode it can violate other modes. so multi modes helps a lot in this situation. There is one more point about multi mode is that we can do area recovery at stage if we define all modes in a design. This helps in routing congestion a lot. I have eone question about the run times of soc in while doing multi mode timing optimization if design is large. Thanks Anil