Terrible VSE output performance when rending I use Blender as VSE.

I was going to edit some clips. my setting is in screenshot.

Blender version: 2.81a, download from Steam.

OS: Win7-64bit

My Hardware:


i7-4790k with 16G memory
Nvidia Geforce GTX1080


I just cut a video into 3 pieces, removed the middle one, and removed the gap. No other effects, nor anything else.



When I click Render Animation, the preview window pop out. It is terribly slow, like under 15fps. My outbut should be generated as 60fps, means a 5mins video needs 20mins to render. That performance is horrible to me.

I checked both my CPU usage and my GPU usage. CPU is used by 20%. None of GPU is used. Both of them are not decently used by rending.

(Drivers are correctly installed because I can use NVENC by using Avidemux, and also games)

What should I do to get a good performance when using Blender as VSE?
Install the Parallel Render add-on: https://github.com/elmopl/ktba/blob/master/scripts/addons/parallel_render.py

Use it like this way:
https://github.com/elmopl/ktba/wiki/Addons