Harry Muscle said:
The Ramdac doesn't have too much to do with actual video quality, at least
it doesn't with NVidia cards. Assuming that NVidia and ATI cards are build
somewhat similarily in principle, it would be the low pass filter that
affects that actual quality of the signal. This might be more of a part
that the individual manufacturers can choose for themselves, just like with
NVidia cards. However, I too have read that Sapphire produces cards with
very good video quality.
You're referring to a fairly well-known problem with older Nvidia TNT and
GeForce cards. There were do-it-yourself mods posted on any number of Nvidia
fansites because the low-pass filters were so bad. The blurriness and
high-res ghosting were legendary.
That doesn't seem to be the case with any of the current cards from either
Nvidia or ATI, though most reviewers conclude ATI's image quality is
slightly better.
As you suggest, RAMDACs are also good enough as to be not much of a
hindrance to image quality on current cards. But that was not always the
case. When the Radeon 9700 came out, it was noticeably superior to the
GeForce4 Ti cards it was competing against, as well as to the previous
generation Radeon 7500 and 8500.
My point was basically that there is no hardware difference I'm aware of
between ATI-branded and powered-by ATI cards that significantly affects
image quality. They're all good.
Tom's Hardware did a head-to-head of Radeon 9700 Pro cards from various
makers last fall, and the image quality comparisons were so close that they
concluded that the variation between performance of the same card on
different monitors was more significant than the variation between different
cards on the same monitor:
"Since each manufacturer and monitor transforms the analog VGA signals
differently, it's hard to derive conclusions from measurements of the cards'
output signals. You can measure certain indicators and the edge steepness,
but that won't reveal much about the display quality with your particular
monitor. In fact, some monitors even have problems with edge steepness
levels that are too high. The only way to be absolutely sure of your
purchase is to check the display quality with your own monitor. Of course,
you'll first have to find a store that installs the card in a test computer
and allows people to bring their own monitors. And that's an almost
impossible task, considering the influence of the Internet on shopping
habits and the tendency to focus on low prices and gloss over sales advice.
.."
