Finally after ages I found the solution which is on many pages on the net but not obvious and should have been standard or more common info!
Instant Solution:
Type this into the terminal (unfortunately the driver config menu doesn't have the option as itis hidden):
nvidia-settings --assign CurrentMetaMode="nvidia-auto-select +0+0 { ForceCompositionPipeline = On }"
Make permanent
Cli........
I've had this issue since Ubuntu 9 and now even on Linux Mint 17 no matter what latest version of the Nvidia proprietary driver that I use. It just becomes slower and slower and only gets better after rebooting or restarting Xorg.
Someone here has it as well
https://askubuntu.com/questions/822449/graphics-becomes-slow-after-a-while/917886
It's very fru........
Fortunately the format is EATX so an EATX case will work and the screw layout is standard.
You will need to remove the HEX/TORX screws that are connecting the stock HP standoffs (meant to slide into an HP case).
XW9400 Motherboard Issues
Size: 12" x 13"
Proprietary Power Connector
Proprietary CPU Power Connector
Proprietary Memory Power Connector
Fan connectors are 4 pin so you will need some kind of adapter.........
I am a huge fan of Linux and the idea of OpenSource but I've said it many times, there are still hurdles in today in 2010 for Linux as a Desktop. Linux is still intended for servers at its very core. This can be changed succesfully though, as Apple has shown us with Mac OS X based on FreeBSD.
Half of the issue is lack of driver support and the other half is the Linux Kernel and Window Manages, KDE and GNome still both don't cut it (but they're getting closer).
I'll........