Please attach screenshots of the Preferences > Graphics and the Hardware options windows see Attaching the screenshot to an issue

Please also run the DirectX Diagnostic Tool
Vista: Click Start > (in start search) Type dxdiag > Click on the programme > Save All Information. Please attach the text file to this issue.

Before you restart Second Life, please attach your latest SecondLife log and CrashReport to this issue. This Knowledge Base article will tell you Where do I find my Second Life diagnostic logs?

Please see these articles in Knowledge Base How can I improve performance ? and How do I check for packet loss (network lag)?

If you're using wireless networking, you should try troubleshooting with a direct wired connection; we allow, but do not support the use of wireless network connections.

This article will show you how to get detailed information about the performance of your computer and the Second Life world Statistics Bar Guide

Thank you : )

• Take a look at the graphics settings in the Preferences window if you haven't already. Try moving the Quality and Performance slider to Low re How can I improve performance ?

• Enable VBO: Enables OpenGL Vertex Buffer Objects. re Graphics Preferences Layout
  Tip: Enable VBO on modern hardware gives a performance gain.

Thank you : )