Xorg crashes with nvidia-310-updates

this machine is a Dell inspiron 1520 , with 2 GB of RAM , and 200 HDD .

running ubuntu 13.04 up to date, left the machine for 30 minutes and screen lock is set to ON!, unlocked the screen then fired up totem to watch a movie , after a couple minutes the following message showed up :

"Sorry, the program "gnome-shell" closed unexpectedly Your computer does not have enough free memory to automatically analyse the problem and send a report to the developers."

then, X was terminated and drop back to the login manager .. logged back in, and the same popup message appeared again , so my suspicion was that it might be an abnormal CPU usage thought it could be Chromium!, so i've switched to firefox opened the same webpages as it's showing on the following screen shot /

http://imgur.com/KCrZGRj

but the abnormal usage kept going back and forth between Xorg and Gnome shell reached %60 - 76 CPU usage !

======================

sary@n1x:~$ lsb_release -rd; uname -a
Description: Ubuntu Raring Ringtail (development branch)
Release: 13.04
Linux n1x 3.8.0-16-generic #26-Ubuntu SMP Mon Apr 1 19:52:57 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
sary@n1x:~$

sary@n1x:~$ apt-cache policy xserver-xorg
xserver-xorg:
  Installed: 1:7.7+1ubuntu4
  Candidate: 1:7.7+1ubuntu4
  Version table:
 *** 1:7.7+1ubuntu4 0
        500 http://mirrors.mit.edu/ubuntu/ raring/main amd64 Packages
        100 /var/lib/dpkg/status

sary@n1x:~$ apt-cache policy xserver-xorg-core
xserver-xorg-core:
  Installed: 2:1.13.3-0ubuntu5
  Candidate: 2:1.13.3-0ubuntu5
  Version table:
 *** 2:1.13.3-0ubuntu5 0
        500 http://mirrors.mit.edu/ubuntu/ raring/main amd64 Packages
        100 /var/lib/dpkg/status

ary@n1x:~$ sudo lshw -C video
[sudo] password for sary:
  *-display
       description: VGA compatible controller
       product: G86M [GeForce 8400M GS]
       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=nvidia latency=0
       resources: irq:16 memory:fd000000-fdffffff memory:f4000000-f7ffffff memory:fa000000-fbffffff ioport:ef00(size=128) memory:fea00000-fea1ffff
sary@n1x:~$

sary@n1x:~$ dpkg -l | grep '^ii' | grep nvidia

ii nvidia-310-updates 310.44-0ubuntu amd64 NVIDIA binary Xorg driver, kernel module and VDPAU library

ii nvidia-common 1:0.2.76 amd64 transitional package for ubuntu-drivers-common

ii nvidia-settings-310-updates 310.44-0ubuntu1 amd64 Tool for configuring the NVIDIA graphics driver

 sary@n1x:~$ free -t
             total used free shared buffers cached
Mem: 1017352 946348 71004 0 2292 129532
-/+ buffers/cache: 814524 202828
Swap: 2457596 613604 1843992
Total: 3474948 1559952 1914996
sary@n1x:~$

sary@n1x:~$ df /
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda1 112829108 11551360 95539664 11% /
sary@n1x:~$

sary@n1x:~$ echo $(cat /proc/meminfo | egrep '^(MemFree|Cached|Writeback):' | awk '{print $2}') - + p | dc
227540
sary@n1x:~$ grep ^VmSize /proc/$(pidof X)/status
VmSize: 246576 kB
sary@n1x:~$

=================

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: gnome-shell 3.6.3.1-0ubuntu4
ProcVersionSignature: Ubuntu 3.8.0-16.26-generic 3.8.5
Uname: Linux 3.8.0-16-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.9.2-0ubuntu5
Architecture: amd64
Date: Wed Apr 3 04:23:22 2013
DisplayManager: gdm
GsettingsChanges: b'org.gnome.desktop.interface' b'clock-format' b"'12h'"
InstallationDate: Installed on 2013-04-01 (1 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-shell
UpgradeStatus: Upgraded to raring on 2013-04-01 (1 days ago)
---
ApportVersion: 2.9.2-0ubuntu8
Architecture: amd64
DistroRelease: Ubuntu 13.04
InstallationDate: Installed on 2013-04-01 (12 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MarkForUpload: True
NonfreeKernelModules: nvidia
Package: nvidia-settings-310-updates 310.44-0ubuntu1
PackageArchitecture: amd64
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 3.8.0-18.28-generic 3.8.6
Tags: gnome3-ppa third-party-packages raring
Uname: Linux 3.8.0-18-generic x86_64
UpgradeStatus: Upgraded to raring on 2013-04-01 (11 days ago)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
---
.proc.driver.nvidia.gpus.0: Error: [Errno 21] Is a directory: u'/proc/driver/nvidia/gpus/0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 310.44 Wed Mar 27 14:51:30 PDT 2013
 GCC version: gcc version 4.7.3 (Ubuntu/Linaro 4.7.2-23ubuntu2)
ApportVersion: 2.9.2-0ubuntu8
Architecture: amd64
CompizPlugins: [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,unitymtgrabhandles,workarounds,scale,expo,ezoom,unityshell]
CompositorRunning: None
DistUpgraded: 2013-04-01 16:38:28,075 DEBUG enabling apt cron job
DistroCodename: raring
DistroRelease: Ubuntu 13.04
DistroVariant: ubuntu
DkmsStatus:
 nvidia-310-updates, 310.44, 3.8.0-17-generic, x86_64: installed
 nvidia-310-updates, 310.44, 3.8.0-18-generic, x86_64: installed
 virtualbox, 4.2.10, 3.8.0-17-generic, x86_64: installed
 virtualbox, 4.2.10, 3.8.0-18-generic, x86_64: installed
ExtraDebuggingInterest: Yes
GraphicsCard:
 NVIDIA Corporation G86M [GeForce 8400M GS] [10de:0427] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Dell Device [1028:01f1]
InstallationDate: Installed on 2013-04-01 (12 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MachineType: Dell Inc. Inspiron 1520
MarkForUpload: True
NonfreeKernelModules: nvidia
Package: xorg 1:7.7+1ubuntu4
PackageArchitecture: amd64
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.8.0-18-generic root=UUID=40c2b4a5-16d9-471c-ad18-4ac382ac7f2a ro quiet splash
ProcVersionSignature: Ubuntu 3.8.0-18.28-generic 3.8.6
Tags: gnome3-ppa third-party-packages raring ubuntu
Uname: Linux 3.8.0-18-generic x86_64
UpgradeStatus: Upgraded to raring on 2013-04-01 (12 days ago)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
dmi.bios.date: 07/11/2008
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A09
dmi.board.name: 0UW306
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA09:bd07/11/2008:svnDellInc.:pnInspiron1520:pvr:rvnDellInc.:rn0UW306:rvr:cvnDellInc.:ct8:cvr:
dmi.product.name: Inspiron 1520
dmi.sys.vendor: Dell Inc.
version.compiz: compiz 1:0.9.9~daily13.04.10-0ubuntu1
version.ia32-libs: ia32-libs 20090808ubuntu36
version.libdrm2: libdrm2 2.4.43-0ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 9.0.3-0ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 9.0.3-0ubuntu1
version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.13.3-0ubuntu5
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.3-0ubuntu2b2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.1.0-0ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.21.6-0ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.7-0ubuntu1
xserver.bootTime: Sun Apr 14 00:19:25 2013
xserver.configfile: default
xserver.errors:
 open /dev/dri/card0: No such file or directory
 open /dev/fb0: No such file or directory
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:

xserver.version: 2:1.13.3-0ubuntu5