[mythtv-users] AMD guide to building a Media PC

Brian Wood beww at beww.org
Sat Mar 3 15:52:55 UTC 2007

On Mar 3, 2007, at 7:52 AM, Yan Seiner wrote:

> Which video card do you have?
> I have a Sempron 3000, which should be enough, and my TV runs at 720p,
> so I guess I should be able to show HD.  But it fails miserably with
> prebuffering pauses and the CPU is pegged > 98%, so something is  
> wrong.
> I have another system with an Athlon XP 2000+, which shows HD content
> just fine at 800x600 on TV out with 65% CPU.
> The big difference between the two machines is that the Sempron has an
> nVidia 6200 whereas the Athlon has an nVidia 5200...  ISTR reading  
> that
> the 5200 is actually better at HD playback?  Can anyone confirm that?

You say the "big difference" but I'll bet there are others. What  
driver versions? What settings (vsync or not etc.)? What options in  
your X configuration file? What buss is the card on and what  
parameters (fast writes etc.)?

The biggest difference I'm aware of between the 5xxx and the 6xxx  
cards is that the 5xxx ones use chroma key while the 6xxx uses  
overlay, but I'm sure there are other differences. I think this shows  
up more in things like the OSD and not so much in actual video  
playback where you're not keying or overlaying as a rule.

Then there's the difference between a Sempron and an Athlon, major  
differences which might well show up in multimedia apps like HD  
decoding. Even the cache difference might be significant. A Sempron  
is a low-end CPU and I really wouldn't expect too much from it.

It's been said that a "modern" AMD processor of the "3000+" rating  
should be able to do HD but I'm not sure I'd consider a Sempron as  
"modern" these days, but I'd still look at your video driver and X  
config settings.

Although AMD denies it, their model numbers really are, or at least  
were, intended to indicate performance relative to a P4 of the same  
vintage, since people were simply comparing clock speeds and Intel  
was obviously coming out ahead.

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