[mythtv-users] Upgrade old or cut my losses and buy new?

[Yan Seiner]

Phil Bridges wrote:
> On 3/5/07, Steven Adeff <adeffs.mythtv at gmail.com> wrote:
>   
>> On 3/4/07, Brian Wood <beww at beww.org> wrote:
>>     
>>> On Mar 4, 2007, at 6:22 PM, Yan Seiner wrote:
>>>       
>>>> Steven Adeff napsal(a):
>>>>         
>>>>> If your motherboard supports it, you can try overclocking the
>>>>> Sempron,
>>>>> you probably don't need much to get it decoding 1080i.
>>>>>           
>>>>    I tried that.  Seems that the limitation isn't the CPU clock
>>>> cycles,
>>>> it's the pitiful cache that AMD put on the chip (128K L2 and no L1).
>>>> Basically, the CPU spins its wheels waiting on data.  More wheel
>>>> spinning isn't going to help.  :-(
>>>>
>>>> Also, that mobo has only one stick of DDR400 memory.  Would there
>>>> be any
>>>> advantage to a second stick?  (Other than more ram, of course.)  The
>>>> system has 512MB RAM.  If I can improve performance for < $100 well
>>>> enough to run HD, I'll be happy.
>>>>         
>>> 1GB RAM would of course be nice but if you're not doing anything else
>>> it should be enough for playback, use free or top to see if you're
>>> swapping excessively though.
>>>
>>> If you *really* want to know more about RAM and HD decoding check out:
>>>
>>> http://www.cs.princeton.edu/~chenhan/papers/icme2002t.pdf
>>>
>>> A bit out of date but the concepts are of course still valid.
>>>
>>> I seriously doubt that CPU will do what you want though.
>>>       
>> yea, I'm gunna have to agree with Brian here (per usual...). I would
>> assume a 3000+ on a frontend only machine should be fine for HD,
>> though I wonder if its enough to enable Bob during playback?
>>     
>
> I run an A64 3000+ frontend/backend doing HDTV fine without XVMC.  I
> believe my X/mythfrontend CPU usage stays around 50-60% while watching
> live.  IIRC, I don't have any deinterlacers working, but I'd have to
> check my machine to be sure.
>   
Does the CPU load come from decoding the MPEG2 stream or from sending 
the data to the video card?

I have an Athlon XP 2000+ that does HD just fine (60% CPU load), but it 
is using the s-video out on a 5200 card.  I am assuming that some 
percentage of CPU horsepower goes to decoding the stream, some to 
rescaling to the appropriate screen resolution, and some to shoving the 
data out to the card?

I am definitely not a video hardware kind of person, so I'm not really 
sure if the above even makes sense, but hopefully someone can puzzle it 
out enough to answer.  :-)


--Yan