[ubuntu-uk] Compositing performance hit
andrew at aoakley.com
Thu Mar 27 10:16:19 GMT 2008
On 26/03/2008, Chris Rowson <christopherrowson at gmail.com> wrote:
> Quick question. Does running Ubuntu with compositing enabled effect
> the overall performance of the system?
> Nvidia Geforce 440
Compositing will not noticeably affect system performance if you have a
separate hardware 3D graphics card that supports full transparency in
hardware. I think that any card that is compatible with DirectX7  or
above will support full transparency. All PCI, AGP and PCI-E Nvidia and
ATI cards since around 1999 should support full transparency.
Your Nvidia Geforce 440 does support full transparency in separate
hardware and will run compositing very fast. I actually have the very
same card on my Ubuntu Dapper machine at home, running Beryl, the
precursor to Compiz Fusion that is used in Gutsy/Hardy.
If you are using Compiz prior to Hardy Beta (eg. in Gutsy), you may need
to tweak your xorg.conf video driver settings to prevent full-screen
video running slowly/jerkily. Various solutions on ubuntuforums.org .
Integrated 3D graphics chips, that are less than three years old, that
use a mixture of hardware and software, and which are soldered to your
motherboard, should be fine for most desktop use, but may slow
considerably when you run full-screen video or full-screen 3D games,
depending which version of which drivers you are using. For instance,
until a recent driver update, my laptop with Intel X3100 i965 graphics
ran full-screen video very jerkily and full-screen 3D games very slowly.
The solution is to turn off Compiz before running full-screen video or
3D games; I did this by creating a separate video/gaming desktop
account. Since the recent Intel driver update, though, full screen video
works fine with compositing turned on in Hardy Beta.
Integrated graphics chips which are older than 3 years, which use more
software than hardware, will definitely see a slowdown and possibly, due
to lack of transparency support, won't work at all. Similarly, any
AGP/PCI 3D card prior to DirectX7 will probably, due to lack of
transparency support, not work at all.
 DirectX is a Microsoft 3D driver and has little to do with
Linux/Ubuntu. I use this only as a useful measure of ascertaining
hardware 3D features, when reading from the side of a box or from a list
of features on a website, prior to purchase.
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