|"Should I try the VGA cable instead?"|
No, you should either be using HDMI or DVI, no adapters.
"I've run through the Vision Control Center Calibration routines for both the monitor and the desktop"
Did you do this? http://windows.microsoft.com/en-us/...
"please, don't tell me that ReadyBoost doesn't work"
I didn't say it doesn't work, I said you only have 8GB RAM. However, ReadyBoost "isn’t a silver bullet that will make your computer faster, although it may be useful in some limited circumstances"
"ReadyBoost only helps if your computer doesn’t have enough RAM. If you have more than enough RAM, ReadyBoost won’t really help."
"In summary, ReadyBoost probably won’t improve your computer’s performance much. If you have a very small amount of RAM (512 MB or so) and a very fast USB drive, you may see some increase in performance – but it isn’t even guaranteed in this situation."
You shouldn't be saying you have 24GB of RAM (effective or not) when you only have 8GB. Try installing 24GB of actual RAM & tell me if 8GB +16GB flash/ReadyBoost performs the same.