[lug] 2D cards

D. Stimits stimits at comcast.net
Fri Apr 28 18:53:11 MDT 2006

Zan Lynx wrote:
> On Thu, 2006-04-27 at 21:51 -0600, D. Stimits wrote:
>>One thing I never see in specs, and which seems important for 2D or 3D, 
>>is how clean the dot clock is. That little square wave that turns pixels 
>>on or off can be sharper on/off in different video cards rated at 
>>otherwise similar specs. The older Matrox G200 really sucks if you try 
>>to scan fast enough on a modern high quality monitor. The older 3dlabs 
>>Oxygen VX-1 (about the same speed as the old TNT2), on the other hand, 
>>is stone cold clean in every way. The two could be set up identically at 
>>slow scan rates and you might not tell them apart; speed them up to 
>>faster rates, and the old VX-1 will probably exceed the quality of a lot 
>>of newer cards. I'd take the VX-1 over any of the older Matrox cards any 
>>day...but I've never seen how the newer Matrox cards look.
> And of course if you're using DVI to a LCD panel, none of that matters.
> Bits are bits.

Tkil mentioned some interesting points, that it matters less, but still 
matters if things get too bad (would be nice to have fiber optic video 
cables with some sort of smart two-way talk). On the other hand, there 
is still usually some equivalent to a RAMDAC, but it's built into the 
monitor itself if it's one of the DVI monitors. What's nice about that 
is that the analog portion of the cable is part of the monitor itself, 
and highly controlled. It's better to have the less controlled longer 
cable as a digital format. Knowing what to pick up would depend on what 
kind of monitor is to be used, and whether there's any chance of future 
expansion. Incidentally, the RAMDAC tends to be sharper and cleaner on 
faster 3D cards just because of the need for the higher frame rates...as 
a side effect, it will also help 2D. Most RAMDACs show their nature at 
the upper scan rate limits, and so even a bad RAMDAC probably is good if 
you keep it at slower scan rates. Meaning that buying a faster card and 
running at slower rates using a cheap card might provide better analog 
quality than buying a very expensive card and running it right at its 
limits (but the cable quality has to be considered even at slower 
speeds...usually the monitor sets this in stone).

The other point about future apps using 3D is probably an 
understatement. Even if you ignore the 3D, at this point I'd consider it 
unwise to buy any computer without PCIe if it has to last a couple of 
years, since video card upgrades are rather important for a lot of uses, 
and there won't be too many exciting advances in AGP. Prices will go 
down for AGP until things are no longer manufactured, but prices will 
keep going down on PCIe for years after AGP is a dinosaur. And currently 
there is no reason to not get a card with a GPU and 32 MB video ram, 
they're as cheap as the old 2D stuff (or cheaper in some cases).

D. Stimits, stimits AT comcast DOT net

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