Geek I am, I run a system monitor graph utility docked to the side of my screen. ABPMON

Over the last few days it has revealed some unusual conditions.

system:
XP Media Center 2002 sp3
3Ghz clock
2GB RAM
Tixati v1.96
seeding 12 low demand torrents
streaming 8k audio in 2 channels

ABPMON monitors and graphs multiple functions, in this case CPUsage was the indicated problem. ABPMON delineates CPUsage into 3 categories: user mode, kernel mode and interrupt, deferred process mode.  In normal function, most CPUsage is confined to user mode. Occasionally tixati will cause a 30-60 second kernel mode surge to 100%. Of late, something new. I am finding my system being swamped with about 60% CPUsage from the interrupt mode. This stays at that level. It is not like the temporary kernel mode surge/spike.

I closed tixati and the interrupt level CPUsage dropped back to its normal 0-1% level. I restarted tixati, perhaps too soon, but it quickly caused the same high level interrupt CPUsage. I rebooted the system and restarted tixati and this issue went away with overall CPUsage floating around 10%, with usermode at 4-6%, kernel mode at 3-4% and interrupt mode 0-1%

I have been running this basic setup for months now. This new condition just began in the last few days...why?

The only thing I can think of is that I started experimenting with video streaming, not using this client but another that was joined to the same channels. I occasionally watched the stream from this client to test, but most of the time it was simply idling in the channel where the video was being streamed. Coincidence? certainly possible. But I don't know any procedure to determine what is causing the extreme interrupt mode CPUsage.

For now, I decided to turn the video streaming off and see if this condition returns. If not after a while, I'll turn it back on and see if it precipitates this condition.

Any other tips on determining the cause?

follow up testing.

3 days uptime and tixati was solid, very low CPUsage

I decided to grab a video file off my other system using tixati, then to start test streaming it.

Interesting thing happened on the way to do that.  Since it was shared over my LAN, the transfer speed was 2 MB/s and the 225MB file finished transferring in under 2 minutes.

All was well for the first 10 seconds or so, with CPUsage rising a little under this load. INT CPUsage rose to 5-10%, then it jumped to 35-40% and stayed there, even after the transfer was complete. User mode and kernel mode CPUsage dropped back down to normal range, but even 15 minutes later the INT mode CPUSAGE remains flatlined at that 35-40% range

Closing Tixati to see if it will clear on restart.
All modes of CPUsage dropped, now showing 0% User, 1% Kernel and 5% Int Mode when averaged at 5 sec intervals.
Int mode level seems to still be above normal idle rate.
Restarting Tixati after a 10 minute rest, INT mode CPUsage surged to the 35-40% rang and stayed at that level.

System reboot appears to be needed to correct this issue.

After system reboot, Tixati started with normal CPUsage stats.

Then I noticed another peculiarity related to RAM ans SWAP
On start, 40% of RAM was in use, SWAP 0%. Then gradually over the next 10 minutes, the RAM tapered off while SWAP sloped up very gradually, leveling off at 19% after 10-15 minutes. RAM usage dropped to the 25% range.

I'll restart again with tixati auto-start turned off, to see if this is causing the SWAP usage.

The RAM>SWAP issues is not related to tixati. Without tixati or any other ap running, except for TSR utilities, the SWAP ramped up to 18% ... So the INT mode CPUsage issue remains the focus.