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AR# 16225

6.3i/6.2i/6.1i XST- XST takes a long time to synthesize


Keywords: XST, synthesis, long, run time, ISE

XST takes longer than usual to synthesize a number of my designs.


Issues associated with the creation of the RTL Viewer netlist (".ngr") cause XST to take a long time to synthesize. Turning off the RTL Viewer netlist creation can speed up synthesis run times.

To turn off RTL Viewer netlist creation from within ISE:

1. Right-click the "Synthesize" process.
2. Select "Properties".
3. Change the "Generate RTL Schematic" setting from "Yes" to "No".

This issue has been fixed in ISE 7.1i
AR# 16225
Date Created 09/03/2007
Last Updated 01/06/2009
Status Archive
Type General Article