OS X 10 10 Yosemite Hands On Video Walkthrough and Review HD

OS X 10.10 Yosemite Hands On Video Walkthrough and Review Mac OS X 10.10 Developer Preview Free download Mac OS 10.10 today I install OS X 10.10 on my MBR Late 2011 yesterday. I have some problem: 1. Safari be slow and lag 2. Boot time too long than Maverick 3. Flash error.... My MBR spec: MBR Late 2011, i5 2.4Ghz, Ram 8GB, SSD 60GB, VGA HD 3000