As for me, I didn't even notice, that something changed with 1.8 -> 1.9 upgrade. Everything was working, works and hopefully will be working as intended. From performance demanding things I use mplayer (1920x1080 videos through HDMI on my big TV screen), psx emulator and perhaps something else. No performance decrease detected. I use Lenovo Thinkpad SL500 with Intel GMA 4500MHD.