The Virtex-4/-5 devices can run SelectMAP 32 at 100 MHz. When configuring in wide configuration modes at high speeds, the device requires a setup time after INIT goes High before the sync word can be applied to the data pins on the interface. This setup time is the time from when INIT goes High to when the interface is ready to accept data.
In previous versions of the software, there were 32 bits of pad words in the bit file. With SelectMAP8, the device had four clock cycles of setup time after INIT went High before valid data was presented. Since the introduction of 32-bit mode BitGen, when data is presented as soon as INIT goes High, the device has only one clock cycle of setup time.
This problem has been fixed in the latest 9.1i Service Pack available at:
The first service pack containing the fix is 9.1i Service Pack 2.
This Service Pack corrects this issue by providing ample time when running SelectMAP32 at 100 MHz for the device to setup if data is presented as soon as INIT goes High.