Sandy Bridge / Desktop Effects

am i the only one where the "desktop cube" yb switching worksapces and 3D effects with ALT+TAB are no longer working since some time? this all worked since nearly a year ago and after update to F15 for a very long time - what is going on here? 3.3.5-2.fc16.x86_64 KDE 4.8.3 (also older KDE releases) xorg-x11-drv-intel-2.17.0-8.fc16.x86_64 _________________________________________ Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz 00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09) 00:01.0 PCI bridge: Intel Corporation Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port (rev 09) 00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) 00:19.0 Ethernet controller: Intel Corporation 82579LM Gigabit Network Connection (rev 04) 00:1a.0 USB Controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 04) 00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 04) 00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b4) 00:1c.4 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 5 (rev b4) 00:1c.6 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 7 (rev b4) 00:1c.7 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 8 (rev b4) 00:1d.0 USB Controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 04) 00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev a4) 00:1f.0 ISA bridge: Intel Corporation Q67 Express Chipset Family LPC Controller (rev 04) 00:1f.2 SATA controller: Intel Corporation 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller (rev 04) 00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 04) 01:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection 02:00.0 USB Controller: NEC Corporation uPD720200 USB 3.0 Host Controller (rev 03) 03:00.0 Network controller: Atheros Communications Inc. AR5008 Wireless Network Adapter (rev 01)