I have been around the world on this one.
I have recently replaced my graphics card with a newer Radeon HD 4670 and updated as customary the drivers for the card for my Windows 7 64 bit OS. I rebooted and tested everything out and was amazed at the performance.
It ran GREAT until, this morning I am back to the SAME performance issues experienced with my last card it replaced. I have to tune down the Aero Interface to the basics. If I do not animations and all the goodies that make Win 7 nice to use are dog slow.
Please keep in mind I have (3 mos ago) performed a fresh install of Win 7 on a clean drive AND updated my BIOS and all relavant drivers for my system.
My issue I believe is WINDOWS and not graphics.
Something occured last might with the restart of my system, EXACTLY as it did on my previous card - It ran like a brand new PC with all Aero affects UNTIL a reboot took all the magic away.
I used to build my own PCs (10 years ago) however havent done much lately except this. I am fairly clear on the importance of proper BIOS and driver updates when configs and OS changes occur however I simply do not understand what is causing the same issue now on two cards of different generations.
Windows Aero stutter while opening and closing windows is well known. Windows Vista, of all the operating systems, actually works way better in this department.
If you are complaining exactly about what I am talking about, it is quite possible that it is Windows and not your hardware. You can try disabling the write cache for your hard disk and see if there is any difference (just to try out). Go to Device Manager, select the OS hard disk, go to Policies, uncheck the write cache option. Note that this should affect your hard disk performance a bit.
I am not sure what happened after that restart when you got all the magic in the house.
If you have the patience, try installing Vista and see if you find those effects better, you will then know who is the culprit.