Facing minor stutter but no performance drop.

I have been facing stutter in games on my new machine. i updated my video drivers as well as my mobo drivers.
i get stable fps in games ..in bf3, i get most of the stutter. the fps doesnt drop below 60 but stilll it stutters.
and my windows is also acting strange lately. takes time to open my computer or any stuff on the computer. sometimes it's fast and sometimes it takes time.
i monitored gpu and cpu temps. gpu temp goes max 70c while gaming . and cpu temp stays in 60's . in bf3, max it goes till 69c.

my rig:
intel i5 2500
gtx 560 ti
8gb ram
asus p8h61-M LX
silverstone strider 500w
500 gb seagate + corsair force series 3 60 gb