[mythtv-users] Source of my IOBOUND problem?

[Craig Huff]

I could use some help identifying the source of my IOBOUND problem or how to find out
what the source is.  Perhaps I'm just getting lost not seeing the forest for the trees.

I have the following setup:

Software, courtesy of Axel's atrpms:
Fedora Core 6, kernel version 2.6.20-1.2944_1.fc6.cubbi_suspend2
NVIDIA driver nvidia-graphics9755.i386, version 1:1.0_9755-86.fc6.at (and related rpms)
mythtv-suite.i386, version 0.20.1-156.fc6.at

Hardware:
Asus A8N-SLI Premium motherboard with Athlon 64 3200+ CPU
Hauppauge PVR-350 PCI
Hauppauge PVR-500 PCI
Adaptec AHA-2940 PCI SCSI adapter
Gigabyte GE Force 7300GS PCI-E Video w/ S-Video, VGA, and DVI-I ports
512MB RAM
Western Digital WD2500JB PATA 250GB HD
+ other stuff probably not relevant to issue ;-)

My problem is that this system gets all tied up in knots if I try to record two or three shows
simultaneously, or worse yet, have the temerity to try and burn a DVD or play a show
concurrently.  From what I read in the wiki, on this list, and elsewhere, this system should
be loafing under this load, and yet...

I had thought PCI bus latency for the disk drive might be relevant, but I have learned that
the PATA interface is part of the NVIDIA nForce4 chipset on the mobo so it's not a PCI
connection.  ivtv pushes all three capture cards' latency from 32 to 64.  The SCSI card
is reported by lspci -v to have latency set at 32, although I'm not trying to read or write from
the tape drive while doing this test ;-).

All I can really tell is that the data isn't moving fast enough, but not why.  Any insights
would be greatly appreciated.

Here are snippets of logs I collected when the system is bogged down.  Let me know what
important thing(s) I forgot to tell you, and many thanks for all the help given so far!

# hdparm -i /dev/hda
 UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5