This Design Advisory was most recently updated on February 14th, 2013 with the following details:
The Vivado Design Suite 2012.3 and older versions were under-reporting delays on some of the longer paths of a device for 7 series designs.
The timing engine and speed files were updated in Vivado Design Suite 2012.4 to address this situation, which can cause the TNS and WNS (timing scores) to increase.
The following is an overview of the steps to take to review the impact of this change on your design in Vivado Design Suite 2012.4 and newer versions:
1. Assess timing analysis results for an increase in the TNS and WNS (timing scores)