Hombre, yo he visto a la venta cables VGA de hasta 30 metros, supongo que si lo fabrican será que, por lo menos, hasta esa distancia funciona.
Saludos
Edito:
Acabo de ver en un foro que comentaban esto:
"VGA-Analogue is not going to have as long a range. Using high quality cables I would say that 10 meters would be the maximum for 1024x768@60Hz. There are VGA-Analogue repeater solutions as well that can also permit 10's and 100's of meters of signal--at lower
resolutions--e.g. 800x600@60Hz."
Asi que puede ser que a mayor distancia menor resolucion y refresco