I just recently updated to my video card's new drivers (v11.5), and I get massive lag spikes every 1-2 seconds. Happens to a very lesser extent upstairs (maybe every 10 seconds or so), but every 1-2 seconds downstairs and outside. Happens both with Ender's and vanilla client, but less with the vanilla one.
Probably has something to do with the driver update, so should I try to downgrade (if possible) my driver version, or wait for a fix?
PS. AMD video card owners do not update your drivers.