I installed ISE 6.1 with the service pack and my Spartan IIe design that worked fine under 5.2 no longer works in the timing simulation in 6.1. Also, the number of Slices used increased by 10% as well as the TBUFS. I have fiddled with almost every combination of options in the synth, map, and par to try and recreate the better results I had in ISE 5.2. I talked to Xilinx and they just told me to fiddle with the parameters some more. Has anyone else had similar problems migrating a project from 5.2 to 6.1?
Regards, Colin