| Sony Vegas | How to improve preview performance?

Question

Video processing

Hello!
Sony Vegas Pro 13
I work with Sony Vegas, to be more precise, I do "navels".
When I insert some FX effect over the video and see it on the preview, it slows down terribly.
I tried to increase the amount of RAM to 2 GB (On a computer 8 GB and 16 virtual) in Preferences, but it did not help.
Set Preview Quality to Best - Full.
Nothing helps, but after the final render (internet 720p) FX (explosion for example) is not buggy, and goes clean. But this is the final render, and I have to do the "live" navel.
PS: Of course, I understand that "navels" are pranks and others, but still ...
CPU - AMD A-10 4655M (4 x 2.0 ghz)
Graphics adapter - AMD Dual graphic HD 7620G + 8600M (Radeon)
RAM - 8Gb ,
Windows 8.1 - license

Answer 1

set preview quality to as low as possible - this is the only way you can save rendering resources.

Answer 2

use a preliminary calculation of the selected area (RAM Preview), Shift + B, the value in the settings is responsible for this, and not for realtime