So I fixed the flickering by clicking on "Force Full GPU Scaling" in the preferences, then it worked fine again for a few hours, then started again.
[110427.372121] NVRM: Xid (0001:00): 6, PE0000 0200 07800000 0000fdc8 00ffffff 00000000
[110427.389366] NVRM: Xid (0001:00): 30, L1 -> L0
I post this as the Xid is slightly different. Hopefully this helps.