http://support.amd.com/us/kbarticles/Pages/GPU57RemoveOldGraphicsDrivers.aspx
New drivers for Radeon 6310:
http://support.amd.com/us/gpudownload/windows/Pages/radeonaiw_win8-64.aspx
Measure DPC latency: http://www.resplendence.com/latencymon see if a specific process is causing the issue. Also check this out: http://superuser.com/questions/550478/windows-8-stutters-lags-on-video-playback Similar issues.