What is the reason for the blurry image (defocus) when connecting DVI -> VGA?

Question

ASUS

I have a slightly blurry image on the display.
The connection is: PC (Video card; DVI) -> Display (VGA).
There is an option to connect a PC (DisplayLink; USB) -> Display (DisplayLink; USB), the image is crystal clear, but with this connection, the PC is buggy due to the operation of the DisplayLink software adapter.
How to get a crystal clear picture when connecting PC (Video card; DVI) -> Display (VGA)?
System:
OS: Windows 10 (10240) Pro, 32-bit
CPU: Intel Q6600 @2.40GHz x64
RAM: 2 GB
Display:
ASUS VW223B
1680x1050
66KHz 60Hz
Video card:
NVIDIA GeForce 8800 GT
256MB
Images:

spoiler

Чистое изображение (DisplayLink)	DVI -> VGA

Answer 1

The reason is that it is VGA. Analog interface, any signal problem is immediately visible.
You can try to replace the cable / adapter. Your best bet is to ditch VGA and buy a normal DisplayLink adapter.
As an option, run auto-tuning on the monitor and / or rotate the phases with the knobs. I have never seen auto-tuning fail, but anything can happen.