[mythtv-users] PCI Graphics card and HDTV

Rod Smith mythtv at rodsbooks.com
Sun Feb 4 04:09:45 UTC 2007

On Saturday 03 February 2007 22:32, Matt Jordan wrote:
> > That and the PCI bus does not have the bandwidth required for HDTV
> > without XvMC (which lowers the amount of data being sent to the card).
> Ahh, okay.  So I can get away with a slower processor as long as there
> is adequate bandwidth to the GPU (i.e. AGP 4x/8x)?

Not, I suspect, as slow as the 1.5GHz system you're contemplating. The amount 
of acceleration provided by XvMC is NOT enough to let a 1.5GHz Intel CPU 
reliably play back HD content, even over an AGP bus. As I wrote in my last 
message, playing back HD content on my system with a 3.06GHz Celeron and an 
AGP video card based on the nVidia MX4000 chipset consumes 50-60% CPU time 
just for mythfrontend, with another 10% or so going to X. If the VIA CPU you 
asked about originally is no more efficient (on a GHz-to-GHz basis) than my 
Celeron, that means it simply won't be able to keep up with HD playback, at 
least not unless there's some other factor at work, such as a vastly superior 
XvMC implementation (both hardware and software) than is provided by the 
binary nVidia drivers and an MX4000-based card.

That said, I don't know much about VIA CPUs. If they provide significantly 
more processing power per GHz than Intel CPUs, a 1.5GHz CPU might be 
adequate. I suggest you look for benchmark tests of the 1.5GHz VIA CPU you're 
considering. I'm personally skeptical that it'll be fast enough for your 
purposes. If so, I'd recommend you look for something based on a 3GHz or 
faster Intel CPU or an AMD marketed as a "3000+" or faster.

Rod Smith

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