Im Having The Same Issue - When It Happens I Log Out Of Second Life For A While - Come Back Its Normal -
This ONLY Happens With Second LIfe....NO Other Program Or 3D Game - JUST SECOND LIFE
Screen Shot Click Here
Second Life 3.3.4 (262321) Jul 24 2012 04:02:05 (Second Life Release)
Release Notes
CPU: Intel® Core2 Quad CPU Q6600 @ 2.40GHz (2400.08 MHz)
Memory: 3322 MB
OS Version: Microsoft Windows Vista 32-bit Service Pack 2 (Build 6002)
Graphics Card Vendor: NVIDIA Corporation
Graphics Card: GeForce 8800 GTS/PCIe/SSE2
Windows Graphics Driver Version: 8.17.0013.0142