Plenty of free space, DMA had been checked already, & with the number of DVD trades I do, I defrag regularly.
I do use SpySweeper, Ray. It seems to be the best.
But...after 3 different anti-virus programs, updates & sweeps with each, I finally found the problem: 3 Trojan Horses.
Only DVD I've burned since the fix was with DVDShrink, so I couldn't see the buffer use, but I could tell that it ran muuuuuch faster. And the "rip" to HD with DVDDecryptor was also way faster. I usually extract DVD video with it at 2X, this one averaged 2X & peaked at 2.2X. So I'd say the problem is fixed.
Thanks everyone for the help, it's very much appreciated.
+Ts all around