Thanks Keith for replying so quick.

one more is question : I have sql server 2008R2(RTM) and two production database is running. And from one week client has complaining slowness issue. I have checked evrything like cpu usage, memory, profiler. everywhere its showing normal.

is there any possibility , the slowness issue is because sql server version.

do i need to upgrade the sql server 2008R2(RTM) to sp2 ?