I liked NVidia graphics card because they are well supported in Linux. NVidia is always ahead of ATI in terms of release frequency and have better support for their Linux Drivers.
Recently, NVidia released a new update 295.40 which is supposed to fix security vulnerabilities. It does fixed the bug, but it also introduces a nasty regression that even the developer is urging NOT to use this driver in their forum discussion. The regression affects chip older than G80, inclusive. This includes the full GeForce 6 and 7 series as well as GeForce 8800GTX and first-gen 8800GTS. The symptoms can include graphical corruption, performance issues, crashes and temporary hangs.
Well, here's how i found it. I just upgraded my Linux Kernel to the latest version available, Linux Kernel 3.3.3. It was released by Greg yesterday and i wanted to use this Linux Kernel on my base. It was a good chance for me to get a new Linux Kernel that is build using the latest GLIBC and GCC on Slackware-Current.
As usual, i left the compiling process while i went to the office this morning and when i got home, i just need to finish the process by copying the images to /boot and update lilo configuration file and reboot. Next was re-installing NVidia driver, VMWare, and VirtualBox which need to be recompiled after the kernel changed.
After all of them were finished, i ran startx and i got a messed desktop. The KDE process didn't completed successfully, i got no task bar, and many other problems. I recall in Phoronix that the latest NVidia driver were having an issue and i tried to downgrade to 295.33 (luckily i still have the backup) and the problem is gone now. So it's true that NVidia 295.40 is the culprit.
For now, if you have NVidia graphic cards older than G80, please stay on 295.33 until NVidia update their Linux drivers.