videos

I just finished my new El Capitan build, using the mac mini deluxe guide on this site. Instillation went amazingly smooth, but now i cant get any video to play. itunes or non itunes video(videos from dvds). This was with no graphics card at all, just using the integrated graphics on the mother...

I've noticed that system completely freezes while I watch on HD videos, on YouTube, from my disk with QuickTime etc. . If I watch lower resolution videos like 480p there are no problems. The system completely frezees after 20-30 seconds after hitting play button. I'm using Ati Radeon HD 5670...