[mythtv-users] New installation, choppy video (not DMA) help request

[Marco Nelissen]

>Hello all,
>
>I've been working on a MythDora machine for a few weeks now, in several
>hour increments.  I have a system that seems to be working, but HDTV
>playack performance is poor.  This includes watching "live" TV.  I get
>very high CPU usage from X and mythfrontend (50% each) in top.  The video 
>and audio both have noticeable (but not extreme) chop.  I have checked the 
>FAQ lists that I could find, and don't see any help so far.  This is the
>system info that I can guess might be relevant
>
>MSI K8N Neo2 platinum MB
>AMD Athlon64 3200+

Another poster mentioned that this is insufficient for HD, but don't
rush out and buy a new CPU just yet: I have an Athlon 3200+ also,
and it is perfectly capable of decoding HD without using XvMC.
However, if you need to deinterlace with this CPU you will most likely
run into trouble. Does this problem occur on 720p broadcasts also?
If so, the problem might be elsewhere in your system.
Have you actually measured the throughput of your disk? I set up a new
machine recently and at first it was using the "generic IDE" driver,
which caused extremely poor disk performance and high CPU usage while
accessing the disk, even though hdparm showed DMA being used. After
recompiling the kernel with the right driver for the chipset, speed
greatly increased and CPU usage dropped to almost nothing. In other
words: make sure your disk performance is really OK, and don't just
rely on some tool showing that DMA is enabled.