This is a simplified guide to modifying a graphics card for better image quality.
This guide assumes that the user following it is capable of using a soldering iron/ gun and is fairly proficient with it. The user should be comfortable with working with SMT/ SMD components.
Note that any modification will void the warranty (if any) and I'm not responsible for any damages/ injuries/ loss of life incurred.
CRT users are much more likely to note a difference than LCD users. This is only applicable for analog outputs. ie. VGA or DVI-I connections
It'll not improve DVI-D (digital) connections.
It'll also be much less effective on cards using high quality components on the analog output.
Examples are Matrox cards which already utilise high-quality components and more harm than good would be done if this mod is done on them.
First of all, I'll explain why this modification can improve image quality.
Almost, if not all, video cards have a low-pass filter on the VGA output. This filter serves to remove RF interference.
A low-pass filter's job is to remove all frequencies above the designated cut-off point.
Any interference that is of a higher frequency than this cut-off point will then be eliminated before reaching the display. This is in the ideal world.
However, the components used to create this filter usually have varying values from listed. Usually +/- 20% or +/- 10%.
If you set the cut-off point to exactly the bandwidth of the card, you'll find that in some instances, part of the video information is cut-off as well. This will reduce image quality.
Cheaper cards use cheaper components which are less stable in value and so they may deviate too much and cause the filter's cut-off point to fall below the video bandwidth.
Better cards like Matrox cards have better components that are tighter in tolerance and are much less likely to do so.
Other factors include heat & vibrations but these are not faults of the manufacturers.
So what you can do is to either rebuild the filter with high-quality components (which is unlikely as it takes too much effort and money) or to remove it and hence remove the possibility of it reducing video bandwidth.
This guide teaches you how to identify the components to remove.
This is a close up of the low-pass filter (formed of inductors and capacitors). It is usually formed out of 9 capacitors and 6 inductors.
Some cards may leave out a set of 3 capacitors and or inductors, so take note.
This filter is usually located on top/ below the card but always very close to the vga output connection.
The inductors are boxed in red and the capacitors are boxed in green. You'll note that inductors are usually labelled with a 'L' prefix and capacitors are labelled with a 'C' prefix. It's kind of an inductry standard. In this instance, my card was labelled with 'SL" & 'SC' instead.