[mythtv-users] HD Woes (so close to working, dual-channel RAM question)

Brian Wood beww at beww.org
Sat Feb 3 15:41:29 UTC 2007

On Feb 3, 2007, at 8:10 AM, Nate Crosno wrote:

> After trowing an even 'bigger' processor at it, I am now able to  
> mostly play
> back 1080i, but it still pauses every few seconds.  The new  
> processor is an X2
> 3800. I bit the bullet on the dual core to hopefully solve this  
> once and for
> all, and be able to comm flag/transcode while watching shows.
> I've been playing with all the settings, but so far the best is  
> using libmpeg2.
> I don't see a difference between any of the interlace methods. All  
> take up 100%
> of one CPU.
> I'm currently running a 720p mode from the mode pool. Even watching  
> 720p videos
> was taking up all the CPU of the Athlon 64 3400 before the new  
> processor (did
> an exchange with newegg).  Because of the 720p problem, I stop  
> worrying about
> trying to get a 1080i modeline to work for now.
> So my current question is how much of a difference does dual  
> channel memory
> make on a Mythtv system?  I am an idiot and did not realize I  
> actually had a
> 1gb and a 512mb stick and not 2x512.  In the bios on startup, it  
> says it's
> running in single channel mode.

I suspect it would not make much if any difference, Myth is not a  
memory access intensive application.

You didn't mention what model mobo you're using but if it allows it  
you might try overclocking a bit, even a 10% O/C can sometimes help.

A lot of the Jetway boards have VIA chipsets which have DMA and PCI  
buss problems. You might look at your PCI latency values, adjusting  
them made a big difference on a VIA-based board I was playing with a  
year ago, though your CPU numbers sure sound like that's your problem.

Sounds like you know to have your Gentoo USE flags set to take  
advantage of SMP and threading.

Also check the obvious stuff like making sure you don't have anything  
unnecessary running, you might also try a minimal X server, if you're  
running something like KDE it can take up a lot more CPU than a  
stripped down X server will.

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