Simulink ODE Solver is taking Too much Time ?

Hi everyone

I have designed a simple Arm model in Simmechanics (2nd generation) and i'm controlling it by 'm'-functions. ODE solver is taking too much time to solve it. But when i actuate same model by ramp or step or any other signal, it gives result in fraction of sec.

I have attached my simulink model picture

. I can't figure out what the problem is. I need some help to solve it. Thanks in Advance..