Same problem here using different programs as firefox, games, openoffice.
I've a 64bit pc with Archlinux and a Geforce 240gt GPU.
I have reinstalled 256.35 and solved for the moment.
[marco@myhost ~]$ uname -a
Linux myhost 2.6.34-ARCH #1 SMP PREEMPT Wed Aug 4 14:31:56 CEST 2010 x86_64 AMD Phenom(tm) II X4 965 Processor AuthenticAMD GNU/Linux