Constant 5% frame drop when capturing. CPU not maxed out.

[CaptainProton]

Hello! This is my first post here tho I offen use the search feature to find answers for problems i've had in the past. Unfortunatly I can't seem to figure this one out at all.

I'm using a Matrox G400-TV in windows 2000.
I've got a Pentium3 933mhz w/ 512mb of PC133memory.

Capturing with VirtualDub 1.4.10
the video format is set to YUY2 @ 352 x 240 (CIF)
and is then compressed with divx 5.0.1 (not pro)
bit rate doesn't seem to affect the drop rate.

I have basic video deinterlace check because the TV signal is interlaced, If I set the performance/quality drop down menu set to fastest I get almost no frame drops but at 'fast' I get a constant 5% drop rate. at slowest I get a steady 10% drop rate. But no matter what I choose the CPU is always bouncing between about 30%-60% it's not maxing out. I don't understand whats holding it back. :-?

BTW if I just capture straight YUY2 CIF then I get little or no frame drops but hey, I only have 10 gigs set aside for capping. YUY2 gives me 30 min of cap time, divx gives me 8 hours with a setting of 3000bps

Any ideas?
thanks in advance.

-edit
I forgot to mention that when I'm encoding a YUY2 formated file into divx (not in real time/capture mode) it can encode like 60-70 frames a second! twice what it should be doing in real time capturing. also if I set the capture format to RGB (24 or 16 bit) CIF then I get massive frame loss... like 60%-70% :o

-edit2
when i'm encoding and I go to set the audio codec Mpeg Layer-3 (mp3) is not listed. I recently reformated my system so thats obvioulsy why the codec is gone but uhm... I don't know how I got it in the first place :D

[zzyzzx]

Try recording with Picvideo (MJPEG) codec of huffyv codec then convert to Divx.