Its hard to say based on the little bit of info you provided. If its an i5, 16gb ram ssd drives and a gtx 680, then somethings wrong. if you have a 4 year old netbook with atom cpu, and 1gb ram, then no, its normal. Playback of what online? What resolution?
you wouldnt walk to a mechanic and say " my car makes a funny noise, fix it".. then just walk away would you? how bout some details?