[mythtv-users] Should I Upgrade Frontend from AMD 3200+ to AMD X2 3800+ (DualCore) ?

[Raphael]

Brian Wood wrote:
> On Sunday 15 February 2009 11:23:27 Raphael wrote:
> 
>> I would disagree strongly with that. Even playing 1080i HD mpeg2 my X2
>> 3800 uses around only 30% usage without xvmc or vdpau. Marginal is a
>> very strong term to use for that. I would more put it "has a huge
>> comfort zone margin". I don't know anything about how it handles h.264
>> though. I've been using this for a couple years now and don't see myself
>> getting rid of it for quite a while since right now it can handle the
>> highest bitrate OTA (and digital cable) I can find.
>> Raphael
> 
> There is a huge difference between MPEG2 and h264, in terms of CPU required to 
> decode in real time. If you are using a high-load de-interlacer your CPU 
> requirements would be even higher.
> 
> Playing back while running a commflag job, perhaps a schedule update and a 
> transcode or two would probably push an X2 3800 pretty hard.
> 
> As you said, perhaps "marginal" is too strong a term, but without VDPAU on a 
> multiple HD-PVR system I'd want something more powerful myself.
> 
> We also have to be careful about using CPU loads from "top", as they are an 
> average only, and decoding tends to spike high at certain times. I have seen 
> posts here from people here claiming 30% to 50% loads that still get tearing 
> on some scenes.
> 

Using a combination of top and a process viewer/manager in ubuntu I can 
be fairly sure of what I'm saying. To clarify my previous post:
When I said 30% I was rounding up from in the neighborhood of 26. I 
haven't seen it spike higher than that. Also, "30%" actually means 60% 
of a single core. I didn't point that out before, but in top if you use 
the processor usage it quotes you at the top, that is total across all 
cores, sort of the same way windows task manager reports usage. Still, 
that's 60% of one core for the highest bitrate mpeg2. My post was just 
to address your point about HD mpeg2. H.264 is another issue, but one I 
haven't run into yet.
cheers