Ok, this is another "pops, clicks, blue screens" issue.

What I'm using:

Motu 424 w/ 24IO
TerraTec EWX 24/96

Asus K8V Deluxe
AMD Athalon 64 3200+
1 GB Mushkin DDR 400
ATI 9200 128mb
WD 60 gb IDE
Samsung 120 gb SATA

Windows XP pro (Sp1a)
Samplitude
Wavelab

Now, I've had numerous problems with this system and have figured most
of them out…but I'm still getting occasional pops that show up on
recordings. Here is a history of what has happened so far:

1. When I first installed the motu everything was totally ****ed. I
was getting constant random pops that were picking up on all the input
channels…this problem ended up having something to do with the
electricity in the building and I got an isolation transformer to run
the computer and motu off of and the pops on the input channels
stopped…but I would still get random but far less frequent pops
through whatever channels I was using as a stereo output.

2. All of the first recordings I did had a constant crackle, that was
different than the sharp pops…this turned out to be some kind of issue
with the virtual memory, and after setting the windows page file to
the recommended number this problem stopped…but I still get the random
intermittent pops from the output and occasional loud sharp pops that
show up on the actual recordings…however the pops that happen in the
output do not correspond at all with the actual pops that show up on
the recording, I can tell by switching to the EWX 24/96 for my stereo
output…and while the Motu output will pop ever few seconds..there are
typically only one or two pops per song.

3. On Occasion the system would hang, or I would get a blue screen of
death, with either "IRQ_not_less_than_or_equal" or "BOOT_CALL_ERROR"
or something like that. Though there were no hardware conflicts listed
in the device manager, I read somewhere that there can still be weird
IRQ problems that windows just doesn't see as a "conflict" for
whatever reason so I uninstalled the MOTU drivers, uninstalled
Samplitude, did a fresh repair install of windows…re-installed the
MOTU drivers, moved the 424 to a different PCI slot, re-installed
Samplitude….and everything worked like a dream…briefly. The day I did
this, there were NO pops what so ever. I recorded for about 5 hours
straight with no pops on playback or the actual recording and I
thought I was home free until..

4. The very next day I booted up the system, and there were no pops
from the motu (which usually start intermittently as soon as windows
boots up). But when I started samplitude I was getting this weird
pulsating crackle on all the input channels….all the settings were the
same as the day before when everything was working perfect…and the
crackle was different than the usual loud pops, and it was coming
through all the channels at the exact same time about once every
second. The first thing I did was raise the buffer to 2048 from
1024…and then the pulsing crackle stopped….but the loud pops in the
output section started again…and continued unaffected by whatever
buffer setting I would then make. After a while I started getting the
blue screens again….so I checked the device manger and there were
still no conflicts listed but I noticed that the Motu and my video
card were both using IRQ 16, so I repeated the un-install, re-install,
process of the day before and moved the 424 to another PCI slot.

5. Now it's been about two weeks and I've yet to get another blue
screen, so I might have fixed that issue with the current hardware
configuration, but I'm still getting the pops. The strangest thing is
that no parameters I adjust seem to affect the pops, and that they
very sporadically from time to time….sometimes it will go 15 minute
without a pop on play back…then others it will happen every few
seconds…some times it will be single pops…then sometimes a series of
quick pops…and the pops that come through the output still don't
correspond with the pops that actually show up on the recording. Those
that do show up in the recorded wav files sometimes look like a drop
out, where there is just a small straight line in the wav, and other
times there is a visible waveform for the pop…like it was a sound
coming through the input.

Anyway, my patience is wearing thin with the motu, does anyone have
any advice?