[mythtv-users] High X CPU usage with 8400GS

[Jim Stichnoth]

On Thu, May 28, 2009 at 8:36 AM, Jim Stichnoth <stichnot at gmail.com> wrote:
> I bought an 8400GS graphics card
> (http://www.newegg.com/Product/Product.aspx?Item=N82E16814187042) to
> try out VDPAU.  The old card was a 7200 series.  With the 8400GS, the
> X process is taking up nearly 100% CPU utilization during myth
> playback, with visible tearing in the middle of the screen.  This
> happens even during SD playback.  The 7200 uses only 30-40% CPU during
> similar playback.  This is with the 180.51 drivers, and without VDPAU.
>  Running nvidia-settings, and examining the X logs, shows that the
> nvidia driver is being used.
>
> One issue is that this is a PCI card, not PCI express.  (I meant to
> experiment using an old PCI-only computer, but changed my mind and
> used the main system instead.)
>
> Is there anything I can do to bring the CPU load back down?  Is this
> possibly a PCI issue?  Will this card be suitable for VDPAU?

Thanks everyone.  It seems the consensus is that PCI is responsible
for the high CPU.  At 1366x768 resolution, 24 bits/pixel, 60
frames/second, that's 180 MB/s, whereas Wikipedia says the 32-bit bus
bandwidth limit is 133 MB/s.  I would probably get acceptable SD
performance (as James Stembridge reports) if I were using the myth
option, whatever it's called, to use the original program resolution
instead of scaling to 1366x768.

In any case, when I get to that point, it sounds like this will be a
good way to validate that I'm actually using VDPAU, just by watching
the CPU utilization.

By the way, after the latest UPS delivery, my wife asked me if I have
a subscription to Newegg.  How funny is that.

Jim