Just like many of you here, I was a frustrated barb who couldn't whirlwind to my heart's content due to random disconnects upon using the skill.
I've tried everything from enabling disable Vsync, changing graphic options, tweaking D3prefs.txt, etc.
I even went so far as willing to exchange my card for an ATI to see whether that would alleviate the situation.
But as I considered exchange my graphics card I thought maybe I should try my luck with the driver.
Sadly, as I checked on Nvidia's website, my driver is the latest one.
Undeterred, I tried out the latest beta driver on Nvidia website... and, voila! Not even one single disconnects for over 3 hours already! If you are using an Nvidia card, try it out and see for yourself!
My card is a Galaxy GTX580 reference model.
Remember to do a clean install - there's a checkbox for this when you unpack the driver for installation. I didn't even reboot for this to work. =))
Please leave feedback and goodluck!