I'm not adverse to using LTS, though I currently have 15.04 installed and don't fancy re-installing, particularly due to the amount that I have to set back up (even after streamlining it). Besides the graphics lag I don't have a problem with this version.
Worst-case scenario I'd re-install 14.04 LTS.
Specs are in first post. What other components do you need?
01:00.0 VGA compatible controller: NVIDIA Corporation GK107 [GeForce GTX 650] (rev a1) (prog-if 00 [VGA controller])
drm 344064 3 nvidia
/dev/dri/card0
BOOT_IMAGE=/boot/vmlinuz-3.19.0-16-generic root=UUID=7b7e4fc7-ddd9-4bd1-a92d-0ec878c6b02f ro quiet splash
/etc/modprobe.d/
/etc/modprobe.d/blacklist-rare-network.conf
/etc/modprobe.d/blacklist-watchdog.conf
/etc/modprobe.d/modesetting.conf
/etc/modprobe.d/vmwgfx-fbdev.conf
/etc/modprobe.d/blacklist-oss.conf
/etc/modprobe.d/dkms.conf
/etc/modprobe.d/alsa-base.conf
/etc/modprobe.d/mlx4.conf
/etc/modprobe.d/nvidia-graphics-drivers.conf
/etc/modprobe.d/blacklist-framebuffer.conf
/etc/modprobe.d/blacklist-modem.conf
/etc/modprobe.d/blacklist-ath_pci.conf
/etc/modprobe.d/fbdev-blacklist.conf
/etc/modprobe.d/blacklist.conf
/etc/modprobe.d/iwlwifi.conf
/etc/modprobe.d/blacklist-firewire.conf
# modprobe information used for DKMS modules
#
# This is a stub file, should be edited when needed,
# used by default by DKMS.
direct rendering: Yes
server glx vendor string: NVIDIA Corporation
client glx vendor string: NVIDIA Corporation
OpenGL vendor string: NVIDIA Corporation
GL_NV_path_rendering, GL_NV_pixel_data_range, GL_NV_point_sprite,
GL_NV_path_rendering, GL_NV_pixel_data_range, GL_NV_point_sprite,
GL_NV_packed_float_linear, GL_NV_path_rendering,
[ 5.527] (II) LoadModule: "glx"
[ 5.645] (II) LoadModule: "nvidia"
[ 5.646] (II) LoadModule: "nouveau"
[ 5.648] (II) LoadModule: "modesetting"
[ 5.649] (II) LoadModule: "fbdev"
[ 5.649] (II) LoadModule: "vesa"
[ 5.655] (II) LoadModule: "fb"
[ 5.656] (II) LoadModule: "wfb"
[ 5.656] (II) LoadModule: "ramdac"
[ 5.656] (II) LoadModule: "fbdevhw"
[ 6.533] (II) LoadModule: "dri2"
[ 6.549] (II) LoadModule: "evdev"
nvidia-smi
-----
Mon May 11 13:17:51 2015
+------------------------------------------------------+
| NVIDIA-SMI 349.16 Driver Version: 349.16 |
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
|===============================+======================+======================|
| 0 GeForce GTX 650 Off | 0000:01:00.0 N/A | N/A |
| 48% 32C P8 N/A / N/A | 981MiB / 2047MiB | N/A Default |
+-------------------------------+----------------------+----------------------+
+-----------------------------------------------------------------------------+
| Processes: GPU Memory |
| GPU PID Type Process name Usage |
|=============================================================================|
| 0 C+G Not Supported |
+-----------------------------------------------------------------------------+
Top w/ drivers installed
top - 13:10:41 up 3:47, 2 users, load average: 0.16, 0.23, 0.36
Tasks: 290 total, 1 running, 289 sleeping, 0 stopped, 0 zombie
%Cpu(s): 4.6 us, 1.2 sy, 0.0 ni, 93.3 id, 0.9 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 8135776 total, 7846988 used, 288788 free, 1689780 buffers
KiB Swap: 8346620 total, 26584 used, 8320036 free. 1384620 cached Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1297 root 20 0 338596 153828 78040 S 6.3 1.9 11:22.13 Xorg
1848 jason 20 0 2376868 728212 95916 S 6.3 9.0 13:57.74 gnome-shell
1951 jason 20 0 2618284 1.087g 124752 S 6.3 14.0 51:37.13 firefox
9315 jason 20 0 559244 181820 77436 S 6.3 2.2 5:59.90 opera
9339 jason 20 0 940636 245228 58736 S 6.3 3.0 1:38.62 opera
1 root 20 0 182864 5536 3640 S 0.0 0.1 0:00.81 systemd
2 root 20 0 0 0 0 S 0.0 0.0 0:00.01 kthreadd
3 root 20 0 0 0 0 S 0.0 0.0 0:00.20 ksoftirqd/0
5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0H
7 root 20 0 0 0 0 S 0.0 0.0 0:08.49 rcu_sched
8 root 20 0 0 0 0 S 0.0 0.0 0:00.00 rcu_bh
9 root 20 0 0 0 0 S 0.0 0.0 0:03.24 rcuos/0
10 root 20 0 0 0 0 S 0.0 0.0 0:00.00 rcuob/0
11 root rt 0 0 0 0 S 0.0 0.0 0:00.05 migration/0
12 root rt 0 0 0 0 S 0.0 0.0 0:00.04 watchdog/0
13 root rt 0 0 0 0 S 0.0 0.0 0:00.03 watchdog/1
14 root rt 0 0 0 0 S 0.0 0.0 0:00.04 migration/1
15 root 20 0 0 0 0 S 0.0 0.0 0:00.17 ksoftirqd/1
17 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/1:0H
18 root 20 0 0 0 0 S 0.0 0.0 0:01.52 rcuos/1
I'm not in the position currently to purge, reboot and re-install.