My Ubuntu install frequently freezes, sometimes showing a black screen (not very common anymore - in my latest installs), some other times the mouse and keyboard just fail to move and respond (not even Ctrl + Alt + F1 works) and some other times I'm able to move the mouse with a huge delay (2-5 seconds) but I'm not able to do/click anything.

I have a pretty strong feeling that this problem is related to my graphic card drivers because:

• after hard reset, I usually get error reports about X.org / jockey
• it's common for artifacts to appear during loading / shutdown / whenever, for instance:
  • pattern filled with £ during log off
  • ugly-colored squared pattern during boot
  • windows that are partially moved (i.e.: only the top half)
  • Firefox renderings that leave the bottom ~30% of the page black

These artifacts appear right before the system freezes.

I've installed Ubuntu 12.04 LTS and after several failed attempts to get my dual monitor setup to work properly I tried installing the new 12.10 version, hoping that this new version would have this problem solved... Unfortunatly, that was not the case, so I reverted to Ubuntu 12.04.

I've tried all the drivers in the Additional Drivers application (even the experimental ones), I've also tried the nvidia-current package from the PPA repository ubuntu-x-swat/x-updates as well as the nouveau OSS driver. Nothing (except no driver at all with a 640*480 resolution) at all seems stable.

Here is the info of my graphic card:

alix@alix-E500:~$ lspci | grep VGA
01:00.0 VGA compatible controller: NVIDIA Corporation G86 [GeForce 8400M G] (rev a1)
alix@alix-E500:~$ sudo lshw -C video
[sudo] password for alix: 
  *-display               
       description: VGA compatible controller
       product: G86 [GeForce 8400M G]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:01:00.0
       version: a1
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
       configuration: driver=nouveau latency=0
       resources: irq:16 memory:fd000000-fdffffff memory:d0000000-dfffffff memory:fa000000-fbffffff ioport:cc00(size=128) memory:fe0e0000-fe0fffff

Right now, I don't even have my 22" monitor connected as I can't even get my laptop display to work properly and without freezes. I've searched, read and tried all that I could (over several fresh reinstalls) to fix the problem, but so far, no solution has proven definitive.

I'm sorry I can't precise which symptom maps to each driver but I've been trying to solve this one on my own without logging what I'm doing, perhaps someone here will be able to point me to a certain-fix solution, if not I'll keep updating this question as I go along.

Please let me know if any more info is needed to pinpoint the exact problem.

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Trying out NVIDIA accelerated graphics driver (version 173).

The scrolling, minimizing / maximizing windows takes between 2 and 5 seconds to finalize. Context menus also pop up very slowly and the typing seems delayed by ~1 second. No critical issues so far.

Firefox rendering of the Save Edits button is consistently messed up (random black lines in the top).

Trying out NVIDIA accelerated graphics driver (version current) [Recommended].

All the delays mentioned above and the buggy rendering of the Save Edits button are gone, but I'm noticing that the whole screen flashes black for a couple of microseconds and while I was writing this test for the first time, the bottom 30% of the screen went black and I couldn't do anything (not even Ctrl + Alt + F1 would work). Had to force a hard reset.

Also, the system hanged a little for a couple of seconds with the fade out of the "Restart" menu.

Trying out NVIDIA accelerated graphics driver (*experimental*beta) (version experimental-304).

Same symptoms as before, it crashed once while I was trying to install Chromium and again after a hard reset when I was trying to remove the driver. The bottom of the screen did not went black and I could move my mouse both times. Ctrl + Alt + F1 didn't work.

The ugly-colored pattern also showed up during the second boot.

Trying out NVIDIA accelerated graphics driver (*experimental*beta) (version experimental-307).

The system crashed as soon as I clicked something. Had to do a fresh re-install.

Trying out Nouveau: Accelerated Open Source driver for nVidia cards.

Artifacts still show up during boot but other than that this one seems stable. As soon as I connected my second monitor, the responsiveness dropped a lot, animations and video are somewhat slow.

I'm gonna try this solution http://askubuntu.com/a/98871/9018 later on.