NOTE: if you have hyperthreading enabled it gets MUCH worse. Consider disabling HT if you are seeing logs of CXPACKET waits first, then reevaluating and if necessary adjust MAXDOP.
where to verify whether hyperthreading is enabled or not?
We have Windows 2003 R2 enterprise edition x64 and CPU is PIII Xeon with speed 2834 MHZ
Thanks