There was a time with 11 before it went gold, where it was undesireable to use the 2xx.x drivers from Nvidia and better to stick with 19x.x.

Is it safe now to use the new ones?

Yep, the issue has been worked around in H11 so there is no problem with any of the 256 drivers now. Nvidia has a proper fix upcoming in an upcoming 260 driver (which I don't think have been released yet). With that driver, the workaround will be removed, but it should be transparent to users.

Thanks, much appreciated.