is one of the greatest editing tricks for improving preview speed.
[I edited most of my earlier videos on a single core 1.6 GHz laptop with 1GB of RAM in MAGIX MEP10 with no preview problems.]
The concept is where you make 2 versions of your footage:
1.) Fast Version - Low Quality, low resolution, lossy fast codec [like MidVid
2.) Slow Version - High Quality, high resolution, lossless slow codec [like HUFFYUV
.avi, or .avs
Edit/Preview with the Fast Version
Export with the Slow Version
However, if you are doing complex effects, then this trick won't help since effects must be generated
by your computer on-the-fly... so the speed of your computer determines the preview speed in that case.