I have a huge system generator core originally developed with 13.2 version. Actually we are updating some projects to the latest version of ISE, the 14.7.
In the final step we consolidate the project generated by SysGen, avoiding hierarchies and flattening and optimizing the design. This can be achieved with the -read_cores optimize xst option in command line mode, and the result is a unique optimized NGC file.
In 13.2 version this synthesis strategy give a result of 19% of occupancy, but in 14.7 the result is a 36%!!! of occupancy. I'm trying to change synthesis options to improve the result, without positive results...
Any idea about what have been changed between versions?