2008版一个时域求解错误

先是一个警告：
The current settings will probably lead to a very long simulation time.
You may improve the simulation speed by:
1.checking the frequency range and units settings
2.extending the simulation frequency range
3.checking the mesh to avoid very small mesh steps
然后是这个错误：
Calculation is aborted due to port memory exception. Please reduce number of ports or simulation duration
不知道这是什么原因引起的？
我算的谐振腔，当频率范围2.7~3G时不出现上面的警告和错误
而当我减小频率范围时就会出现上面的警告和错误，为什么时域求解时，频率范围小会增加仿真时间？
不知道这个跟2008版里新增的adaptive port meshing功能是否相关？
谢谢！