I have found where performance seems laggy like issues with a nvidia quadro nvs 420 pushing 4 monitors. If I change a desktop background it totally locks up requiring a hard reset.
user@MachineName:~/Downloads$ lspci | grep -i nvidia
03:00.0 PCI bridge: NVIDIA Corporation NF200 PCIe 2.0 switch for Quadro Plex S4 / Tesla S870 / Tesla S1070 / Tesla S2050 (rev a3)
04:00.0 PCI bridge: NVIDIA Corporation NF200 PCIe 2.0 switch for Quadro Plex S4 / Tesla S870 / Tesla S1070 / Tesla S2050 (rev a3)
04:02.0 PCI bridge: NVIDIA Corporation NF200 PCIe 2.0 switch for Quadro Plex S4 / Tesla S870 / Tesla S1070 / Tesla S2050 (rev a3)
05:00.0 VGA compatible controller: NVIDIA Corporation G98 [Quadro NVS 420] (rev a1)
06:00.0 3D controller: NVIDIA Corporation G98 [Quadro NVS 420] (rev a1)
user@MachineName:~/Downloads$ uname -a
Linux MachineName 4.4.0-28-generic #47-Ubuntu SMP Fri Jun 24 10:09:13 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
Repeatedly in kern.log I see the following.
Jul 14 09:25:18 MachineName kernel: [ 5271.421540] vgaarb: this pci device is not a vga device
Jul 14 09:25:28 MachineName kernel: [ 5281.417966] vgaarb: this pci device is not a vga device
Jul 14 09:25:28 MachineName kernel: [ 5281.417991] vgaarb: this pci device is not a vga device
Jul 14 09:25:28 MachineName kernel: [ 5281.424447] vgaarb: this pci device is not a vga device
Jul 14 09:25:28 MachineName kernel: [ 5281.424471] vgaarb: this pci device is not a vga device
Jul 14 09:25:38 MachineName kernel: [ 5291.420845] vgaarb: this pci device is not a vga device
Jul 14 09:25:38 MachineName kernel: [ 5291.420864] vgaarb: this pci device is not a vga device
Jul 14 09:25:38 MachineName kernel: [ 5291.424406] vgaarb: this pci device is not a vga device
Jul 14 09:25:38 MachineName kernel: [ 5291.424425] vgaarb: this pci device is not a vga device
Jul 14 09:25:48 MachineName kernel: [ 5301.408978] vgaarb: this pci device is not a vga device
Jul 14 09:25:48 MachineName kernel: [ 5301.408992] vgaarb: this pci device is not a vga device
Jul 14 09:25:48 MachineName kernel: [ 5301.410869] vgaarb: this pci device is not a vga device
Jul 14 09:25:48 MachineName kernel: [ 5301.410881] vgaarb: this pci device is not a vga device
Jul 14 09:25:58 MachineName kernel: [ 5311.422363] vgaarb: this pci device is not a vga device
Jul 14 09:25:58 MachineName kernel: [ 5311.422387] vgaarb: this pci device is not a vga device
Jul 14 09:25:58 MachineName kernel: [ 5311.426208] vgaarb: this pci device is not a vga device
Jul 14 09:25:58 MachineName kernel: [ 5311.426230] vgaarb: this pci device is not a vga device
Jul 14 09:26:08 MachineName kernel: [ 5321.442746] vgaarb: this pci device is not a vga device
Jul 14 09:26:08 MachineName kernel: [ 5321.442763] vgaarb: this pci device is not a vga device
Jul 14 09:26:08 MachineName kernel: [ 5321.444894] vgaarb: this pci device is not a vga device
Jul 14 09:26:08 MachineName kernel: [ 5321.444910] vgaarb: this pci device is not a vga device
Jul 14 09:26:18 MachineName kernel: [ 5331.494607] vgaarb: this pci device is not a vga device
Jul 14 09:26:18 MachineName kernel: [ 5331.494631] vgaarb: this pci device is not a vga device
Jul 14 09:26:18 MachineName kernel: [ 5331.504082] vgaarb: this pci device is not a vga device
Jul 14 09:26:18 MachineName kernel: [ 5331.504108] vgaarb: this pci device is not a vga device
Jul 14 09:26:28 MachineName kernel: [ 5341.452516] vgaarb: this pci device is not a vga device
Jul 14 09:26:28 MachineName kernel: [ 5341.452540] vgaarb: this pci device is not a vga device
Jul 14 09:26:28 MachineName kernel: [ 5341.455968] vgaarb: this pci device is not a vga device
Jul 14 09:26:28 MachineName kernel: [ 5341.455989] vgaarb: this pci device is not a vga device
Jul 14 09:26:38 MachineName kernel: [ 5351.485298] vgaarb: this pci device is not a vga device
Jul 14 09:26:38 MachineName kernel: [ 5351.485320] vgaarb: this pci device is not a vga device
From gpu-manager.log
log_file: /var/log/gpu-manager.log
last_boot_file: /var/lib/ubuntu-drivers-common/last_gfx_boot
new_boot_file: /var/lib/ubuntu-drivers-common/last_gfx_boot
can't access /run/u-d-c-fglrx-was-loaded file
Looking for fglrx modules in /lib/modules/4.4.0-28-generic/updates/dkms
Looking for nvidia modules in /lib/modules/4.4.0-28-generic/updates/dkms
Found nvidia module: nvidia_340_uvm.ko
Is nvidia loaded? yes
Was nvidia unloaded? no
Is nvidia blacklisted? no
Is fglrx loaded? no
Was fglrx unloaded? no
Is fglrx blacklisted? no
Is intel loaded? no
Is radeon loaded? no
Is radeon blacklisted? no
Is amdgpu loaded? no
Is amdgpu blacklisted? no
Is nouveau loaded? no
Is nouveau blacklisted? yes
Is fglrx kernel module available? no
Is nvidia kernel module available? yes
Vendor/Device Id: 10de:6f8
BusID "PCI:5@0:0:0"
Is boot vga? yes
Vendor/Device Id: 10de:6f8
BusID "PCI:6@0:0:0"
Is boot vga? no
Skipping "/dev/dri/card1", driven by "nvidia-drm"
Skipping "/dev/dri/card0", driven by "nvidia-drm"
Skipping "/dev/dri/card1", driven by "nvidia-drm"
Skipping "/dev/dri/card0", driven by "nvidia-drm"
Skipping "/dev/dri/card1", driven by "nvidia-drm"
Skipping "/dev/dri/card0", driven by "nvidia-drm"
Skipping "/dev/dri/card1", driven by "nvidia-drm"
Skipping "/dev/dri/card0", driven by "nvidia-drm"
Does it require offloading? no
last cards number = 2
Has amd? no
Has intel? no
Has nvidia? yes
How many cards? 2
Has the system changed? No
main_arch_path x86_64-linux-gnu, other_arch_path i386-linux-gnu
Current alternative: /usr/lib/nvidia-340/ld.so.conf
Current core alternative: (null)
Current egl alternative: /usr/lib/x86_64-linux-gnu/mesa-egl/ld.so.conf
Is nvidia enabled? yes
Is nvidia egl enabled? no
Is fglrx enabled? no
Is mesa enabled? no
Is mesa egl enabled? yes
Is pxpress enabled? no
Is prime enabled? no
Is prime egl enabled? no
Is nvidia available? yes
Is nvidia egl available? no
Is fglrx available? no
Is fglrx-core available? no
Is mesa available? yes
Is mesa egl available? yes
Is pxpress available? no
Is prime available? yes
Is prime egl available? no