[mythtv-users] mythfrontend HDTV performance on recent AMD chipsets (was Re: X2 5000 enough to play HD?)

[Michael T. Dean]

On 08/29/2008 05:41 PM, kanetse at gmail.com wrote:
> Well, it doesn't look like it's a kernel issue.  I installed Fedora 9,
> and the problems continue with the onboard ATI HD3200 video.  I
> attempted to use the MythBuntu Live CD but it turned out the .iso I
> downloaded was corrupted.  Will try with a redownloaded version
> (md5sum checked).

I did some testing last night.  The "Aggressive Sound card Buffering" 
and "Extra audio buffering" settings have no effect (in any combination) 
other than the expected effects.  Enabling "Aggressive Sound card 
Buffering" may or may not speed up seeking and may or may not cause 
playback problems--hard to tell with my unrelated playback problems.  
And disabling "Extra audio buffering" causes jumpiness/"crackly" audio 
in very dark scenes of MPEG-2 video (such as everything I record from my 
HDTV capture cards).

I played with all sorts of BIOS stuff last night, too.  I reset the BIOS 
to defaults (thereby primarily just disabling ACPI 2 and PnP OS) and 
disabled the audio card (I'm using a discrete PCI SB Live! Value I used 
for years because it's a proven one).  Performance was identical.  I 
upgraded to the latest BIOS (nice that the mobo allowed me to do it 
without any floppies--integrated EZ Flash 2 with USB flash drive 
support) and disabled the audio card and--it worked perfectly.  I was 
able to go up to 1.95x without any issues.  At 2x timestretch, I got the 
occasional hiccup, but I would never watch TV that fast, so I wasn't 
concerned.

Then--because I'm not too bright--I decided I would try to figure out 
which BIOS setting was causing issues.  I enabled ACPI 2 and was back to 
the same bad performance (not even allowing 1.05x timestretch).  So, I 
went in and disabled ACPI 2 and enabled PnP OS and--got the same bad 
performance.  So, I went in and disabled PnP OS (leaving ACPI 2 
disabled) and--got the same bad performance.

I'm now leaning toward the issue being due to the Asus AI Overclocking 
(=for some stupid-*** reason, the mobo tries to overclock /every/ system 
by default).  On bootup, it attempts to overclock different parts of the 
system (FSB, RAM, CPU, HT, ...) to their "max" performance.  And, 
coupled with the fact that the PSU is /not/ a 2KW PSU (meaning that 
power on hardware initialization may be "spread a bit thin") means that 
I'm likely getting different system configurations every time I boot the 
system.  I tried turning the AI Overclocking from its default, "Auto," 
to "Standard" and "Manual" (though I'm not even sure that either one 
allows me to disable everything as the descriptions in the documentation 
are far from clear).  I also tried accessing the BIOS's hidden options 
(by hitting Alt-F4 in my BIOS, others user Alt-F1 or different 
keystrokes), but still wasn't able to get consistently good performance.

(OT reference to OC'ers removed...)

On the bright side, though, I seem to be getting a /much/ more 
consistent >10MB/sec throughput on the NIC, now--though I've only 
received about 2GiB.  Previously, its performance would have already 
started to decay.

BTW, I hadn't mentioned, yet, that with both motherboards, I've been 
using an NVIDIA GF7800GTX with the 173.14.12 nvidia driver.  It worked 
great (actually was a bit of overkill) with my previous hardware.

Mike

Wording of description of options for AI Overclocking:

AI Overclocking [Auto]
Allows selection of CPU overclocking options to achieve desired CPU 
internal frequency.  Select any one of the preset overclocking 
configuration options:
 - Manual:  Allows you to individually set overclocking parameters.
 - Auto: Loads the optimal settings for the system.
 - Standard: Loads the standard settings for the system.performance.[sic]

I think whomever edited that description of Standard completely changed 
the wording, but left part of the old sentence in place.  Did I mention 
how much I hate things that automatically break my systems?