Be aware that an updated XML board definition file was posted today in the Documentation area. The filename has changed (zedboard_RevC_v2.xml) and you'll see the datecode reflects August 28th. This latest version fixes an issue with the DDR3 speedgrade that was in the v1 XML. The v1 XML called out the -125 speed DDR3. All ZedBoards to date have been built with -15E:D speed, so the v2 XML now accurately has this.
If you have already created a design, you can fix it without importing a new XML by going to the PS Configuration Memory GUI and selecting the MT41J128M16 HA-15E:D rather than the -125.
Bryan