Why is dithering worse over VGA?

Drake5 · 27 Jan 2012 at 20:43

Recently got this monitor from OcUK - OcUK E2250SWDA 22" - http://overclockers.co.uk/showproduct.php?prodid=MO-062-AC

When connecting via VGA I notice it dithers really badly when looking close. It is VERY noticeable.

When connecting by DVI I don't notice the dithering at all.

Why is it that VGA dithers much worse?

Cheers

kiel367 · 27 Jan 2012 at 20:46

analogue vs digital

Drake5 · 27 Jan 2012 at 20:48

So DVI is always going to be a cripser image?

Xeanor · 27 Jan 2012 at 21:31

Yes, VGA is ancient and should be made extinct.

Drake5 · 27 Jan 2012 at 21:34

So the heavy dithering over VGA is most probabaly normal?

Xeanor · 27 Jan 2012 at 21:36

Yes, pretty much. Though it differs per monitor/cable.

WingZero30 · 28 Jan 2012 at 20:06

I tried 1920x1080p with vga in Battlefield 3 and it was poor compared to 1680x1050 (dvi connection)

Vga is good for low res such as 1024x768 but not for higher res

PCM2 · 28 Jan 2012 at 20:36

It isn't dithering in the sense that the monitor is using an algorithm to make up for shades it can't display. It is simply noise from the analogue signal.

yashiro · 28 Jan 2012 at 20:40

VGA is terrible, full stop.

jak731 · 28 Jan 2012 at 20:45

There was nothing wrong with vga per se but it isn't appropriate for modern flatscreens, it can provide very high bandwidth, eg 100hz @ 1600x1200. Since crts were analogue devices they could use a direct pass through of the vga signal, which is why crts have zero input lag. Flatscreens on the other hand are always digital, the vga signal needs converting from analogue to digital (with an ADC) whereas it doesn't with dvi as dvi is already digital. The problem is most flatscreens have a poor quality ADC so the vga signal always appears poor, with a high quality ADC and cable the difference is less noticeable but vga is still inferior.

gothic_hobbit · 30 Jan 2012 at 01:46

yashiro said:
VGA is terrible, full stop.

I concur.

FallshirmjAEger · 30 Jan 2012 at 19:03

gothic_hobbit said:
I concur.

I also hated how whenever you did manage to unscrew the vga connector, it would also bring the graphic port stand offs that they were screwed into as well :mad:

titaniumx3 · 30 Jan 2012 at 20:09

Depends on the graphics card as well as the monitor. Pretty much every onboard graphics VGA output I've used has been poor, with lots of noise and weird 'wave' artifacts constantly moving across the screen. Even on some early dedicated cards it was a problem. The first card that was free of noise was my 9800pro which was pretty much perfect with no detectable noise; all subsequent ATI high/mid end cards have also been noise free for me.

Also, I found that monitors with only VGA (no digital connections) gave a better image. My old LG 17" was VGA only and quality was pixel perfect with no noise - you couldn't tell it was VGA at all. Plus it was 75hz capable.

jak731 · 31 Jan 2012 at 11:24

Yea all about the DACs and ADCs.

marc2003 · 31 Jan 2012 at 17:34

i've never had a problem with VGA. i had a viewsonic 22inch (1680x1050) which supported both VGA/DVI and i couldn't tell the difference the two. since then i've had 2 completely different LGs which only are VGA only/1920x1080. again no problems whatsoever. whatever issues people have, i don't think there is anything inherently wrong with VGA but it's more likely poor implementation with certain kit.