Whenever the frames dropped to 59 fps it would stutter like a mofo.
Yeah, NVIDIA did something screwy with their drivers when they released "Adaptive V-Sync".
Normally, when you had V-SYNC on, higher frame rates are just capped to the monitor's refresh rate. Lower frame rates were unaffected, and still perfectly in sync with the monitor.
After the driver update, if the frame rate goes below the refresh rate on standard v-sync, it tries to FORCE the frame rate way down to half. So if your frame rate hangs out around 59-60 FPS, it tries to shoot the frames from 60FPS to 30FPS back and forth, causing hideous stuttering.
I haven't seen this since my GeForce FX 5700 LE.
Then, to make things oh so much better, they released adaptive v-sync. With this "feature", any time the frame rate goes below the refresh rate, it COMEPLETELY TURNS OFF V-SYNC. So now, when you get low frame rates, it adds insult to injury by re-introducing tearing. And that's now your only option to get frame rates between 30 and 60.
What on earth happened to good ol' v-sync? I stopped using NVCP v-sync as soon as this came out. In-Game options are now the only way to go.