Hi Trebuchet,
You are quite right about comparisons between non-identical systems. However, I was looking for feedback from others such as yourself, who had tried the new drivers. I did get them direct from NVidia, as a registered owner I received a newsletter which alerted me to their release.
When I benchmarked I did as you recommend and rebooted, I also turned off all other applications including ZA, AVG etc.
I have had a look in a 3D forum and seen one or two others are experiencing similar things. No solutions have yet been proposed but I will keep my eyes open and see if any tweaks etc. come to light.
Meanwhile, I will reinstall the 21.83 as they were performing better in my system. I am not particularly bothered about getting peak performance from my set up but like to keep things ticking along, updating where necessary and/or desirable.
Thanks for taking the time to reply,

Note - I think I need to do some work on formatting stuff for uploading!

:-)