串扰问题？

请问各位大虾，1、HyperLynx对PCB板做快速串扰分析时，需要加入器件IBIS模型吗?2、在加入IBIS模型之后，串扰的值一般是多大，不影响设计?
我在DXP下面找了个example,对其进行快速串扰分析时，不加如IBIS模型，采用默认的模型参数为
Board temperature ................ 20.0 degrees C
  Default IC model (used for quick analysis if IC model is missing)
    IC driver rise/fall time ..2.000 ns
    IC driver switching voltage range ..3.00 V
    IC driver output impedance 1.0 ohms
    IC input capacitance ..... 7.0 pF
串扰门限为
Maximum allowed crosstalk ........... 200 mv peak
特定看一个网络：
  NET = SOFT_TCK
   ELECTRICALLY ASSOCIATED NETS --------------------------------------
     None
   AGGRESSOR NETS (Estimated peak crosstalk)
     NetFPGA1S_B22 .................. 233 mv
     Total estimated crosstalk ....................... 233 mv
     ** Warning ** Estimate exceeds maximum allowed crosstalk！
而我分配模型之后，该网络的串扰增加了很多：
  NET = SOFT_TCK
   ELECTRICALLY ASSOCIATED NETS --------------------------------------
     None
   AGGRESSOR NETS (Estimated peak crosstalk)
     NetFPGA1S_B22 ..................1268 mv
     NetFPGA1S_A21 ..................1053 mv
     NetFPGA1S_A20 .................. 456 mv
     SOFT_TDI ....................... 319 mv
     DIG5_SEG2 ...................... 227 mv
     Sum of the two strongest aggressors .............2321 mv
     ** Warning ** Estimate exceeds maximum allowed crosstalk！

需要加入模型，阈值一般可以通过简单计算得到.不同的电平，阈值是不同的，5v的10%=500mv,考虑串扰是500mv的30%=150mv；