New chipset - M10k performance

markk · Post by **markk** » Sat Feb 28, 2004 12:45 pm

Has anyone else seen this post on the new version of the Nehemiah/M10k chipset?

http://forums.viaarena.com/messageview. ... SGDBTABLE=

Having checked my own cpu, it looks like I've got one of the newer versions - which explains a lot about the performance issues I've been having...

I've modified the myth source to ensure the correct cpu info is reported and as a result my frontend <seems> to be a little zippier. Anyone else tried it and had success?

Regards

Mark

Nem · Post by **Nem** » Sat Feb 28, 2004 2:39 pm

Markk,

For once something is working in my favour ...

processor : 0
vendor_id : CentaurHauls
cpu family : 6
model : 9
model name : VIA Nehemiah
stepping : 1 <<<

BTW was that you I responded to on the MythTV mailing list about Ivors fix to the via slice?

Have you tried it ?

Its working really well here.

Regards,

Darren

markk · Post by **markk** » Sat Feb 28, 2004 4:56 pm

Yes - it was me you responded to. The patch works very well for me too - once I'd spotted the effect it was extremely annoying and the improvement was obvious.

(Are you using RCA or S-Video out? - there is a definite edge effect/blur with RCA and am wondering whether S-Video is any better? - would need a new tv though...)

Regards

Mark

Nem · Post by **Nem** » Sat Feb 28, 2004 5:04 pm

I'm using RCA. I know what you mean about blur. The pictures don't seem as crisp as they should be when compared to the NTL box I have. I wonder if this is another driver issue as my NTL box uses RCA too.

Regards,

Darren

markk · Post by **markk** » Fri Mar 05, 2004 6:39 pm

As per my other post, I've set up a new minimyth frontend this week with a new case and new M10k motherboard.

First thing I did was check the cpuinfo - and it looks like I've got another (newer?) version...

processor : 0
vendor_id : CentaurHauls
cpu family : 6
model : 9
model name : VIA Nehemiah
stepping : 5 <<<<

Not potentially very interesting, but I did a couple of comparisons between the old box and new. Watching the same livetv programs, my old motherboard runs at around 40% CPU using hardware decoding and the new one at around 25-30%, so the changes don't appear to be cosmetic.

Additionally - and this is the really nice bit - the quality of the tv out is much better. DVD playback is on a par with my player and it's difficult to tell the difference between normal tv and myth now. Still a slight fuzziness, but you'd not notice it without looking hard. This could be due to the case - my old case was a DIY aluminium effort (

aheybey · Post by **aheybey** » Tue Mar 30, 2004 12:34 am

I have a M10k with a stepping 5 CPU. According to this post to mythtv-users, stepping 5 has the same bug:

http://www.gossamer-threads.com/archive ... e_P116652/

On my box (MiniMyth 0.4, playing MPEG4) I don't appear to have any functional problems (video plays smoothly), but it uses about 80% of the CPU to play a 480x480 MPEG4 stream.

0. Does this CPU usage seem reasonable or not?

1. Can anyone confirm if stepping 5 has the bug or not?

2. Does minimyth have the work-around already compiled into it?

thanks,
andrew

lmatter · Post by **lmatter** » Tue Mar 30, 2004 12:47 am

Does minimyth have the work-around already compiled into it?

Nope. Minimyth is straigh myth-0.14 with Via Slice enabled.

I'm taking a little break from minimyth development before I start on 0.5 (have to catch up on some other stuff), but I'll look into this once I get back into it.

Larry

markk · Post by **markk** » Tue Mar 30, 2004 2:26 pm

Andrew

I'm not too sure whether 80% cpu is reasonable for MPEG4 as I've never used MPEG4 with Myth.

I haven't investigated fully, but my feeling is that the newest, stepping 5 version does not have the same problem. Performance definitely outstrips the stepping 3 version - but this could be due to other changes they've introduced that haven't yet been spotted. My '5' frontend is almost perfect on my main tv - occasionally losing audio sync after a few channel changes/use of OSD and use of the EPG. The '3' frontend has noticeable stutter problems playing back recordings and loses audio sync more readily.

That said, I also believe there is a bug somewhere in myth. I can seen no reason why video playback should have problems while livetv is always perfect.

I'm going to update to CVS today sometime and start some digging...

Regards

Mark