Hi,
the differences in the 3 models of synthesis:
Wire load model:
This models gives a vague information about R and C values for a given area and fan-out of the cells
RC-PLE:
This models needs LEF of std_cells, memories and IPs and captables of particular corner. From LEF we have the dimensions and area of the std_cells, memories. And from captables we have R and C of nets for given length of the nets.
from this tool calculates the RC and C values.
RC-P:
you have to give the DEF of block for which you are synthesizing. DEF has dimensions of the block, placement information, port information of the block.
So the synthesis tool will have more data of the block. From this the assumptions of the synthesis tool reduced and results are closer to the PnT tool.
Am i clear?