Testing:

MPEG Test using defaults setting
MPEG1 VCD, HalfD1 352x240 CBR 1150, Record 1 min 10.2MB
MPEG2 2.0MBit/sec, FullD1 720x480, Record 1 min 16.0MB
MPEG2 2.0MBit/sec (HalfD1), 352x480, Record 1 min 15.1MB
MPEG2 12.0MBit/sec, FullD1 720x480, Record 1 min 73.6MB
MPEG2 12.0MBit/sec (CBR), FullD1 720x480, Record 1 min 93.1MB
SVCD Extra Long Play, (HalfD1) 480x480, Record 1 min 10.3MB
SVCD Long Play, (HalfD1) 480x480, Record 1 min 13.5MB
SVCD Standard Play, (HalfD1) 480x480, Record 1 min 17.2MB
DVD Extra Long Play, FullD1 720x480, Record 1 min 29.4MB
DVD Long Play, FullD1 720x480, Record 1 min 40.8MB
DVD Standard Play, FullD1 720x480, Record 1 min 51.1MB

Soft decoding CPU Utilization 10% to 50% depend on the MPEG
quality level setting I use and depend on CPU speed.
Note my system has Intel 1.6GHz with nVidia GeForce3 Ti 200.

Each clip record time is 1 min long and done with SageRecorder.
Note: You must have a Soft DVD Player install or MPEG2 codec or
Hardware Decoder to play them back.
All below clip was record from TechTV The ScreenSaver from
DishNetwork 301 NTSC S/Video.
Note: Rigth click on the link and Save Target As.
VCD 1150KB MPEG1 352x240 10.2MB
SVCD 2600KB MPEG2 480x480 17.2MB
CVD 3MB VBR MPEG2 352x480 22.6MB
DVD 4MB VBR MPEG2 720x480 26.5MB
DVD 8MB VBR MPEG2 720x480 51.1MB