HP tx2051 graphics driver

My HP tx2051 tablet PC has the NVIDIA GeForce Go 6150 graphics card in it.  I have been running it with driver version 7.5.11.5682, dated 11/8/2007.  Recently Windows Update showed there was a newer driver, dated 12/20/2008.  I went ahead and updated the driver and reran the Windows Experience Index.  I got the same score as before so the driver didn’t seem to improve the graphics performance.  I did notice that the computer would take longer to recover from sleep or hibernate mode.  The screen would go black for 2-3 seconds before returning to the desktop.  Since the driver update didn’t seem to improve anything I decided to roll back  to the previous version.  I simply used the Roll Back Driver option under the graphics card properties in the Device Manager.  The older driver was restored and the black screen problem went away.