Display adapter for X11R3 386/ix (cont.)

[Karl Denninger]

In article <1990Mar28.170031.10574 at ico.isc.com> scottw at ico.isc.com (Scott Wiesner) writes:
>From article <1990Mar28.032151.7871 at ddsw1.MCS.COM>, by karl at ddsw1.MCS.COM (Karl Denninger):
>> 
>> Next, buy a board which has 
>> an on-board PROCESSOR.  That means something like the Matrox board, or 
>> the Pixelworks board, etc.  I'm not sure about the 8514/A, it may have one.
>> You especially want area-fill and line-drawing intristics on the board;
>
>The 8514 has lines drawing, rectangle filling, and blitting in hardware.
>It's very fast at moving windows, scrolling, text painting, etc.  It's 
>one of the fastest boards we've seen.

Yep.  And expensive.  Then again, you get what you pay for :-)

>> .... Lots of VGA discussion deleted...
>
>Yes, the VGA is a pretty crufty device.  We've spent a fair amount of time
>trying to wring some reasonable performance out of it.  The thing that's 
>most noticably slow is the general blitting (window moving).  Character
>output, line drawing, and to a lesser extent area fill aren't too bad.  If
>you want to speed up the window moving and don't mind sacrificing colors, 
>you can specify 2 or 4 colors instead of 16 in the Xconfig file.  This
>helps out quite a bit for moving windows around because there's less data
>to move.

Correct.  Considering that the processor does everything on a VGA card, and
it's really only an 8-bit data path to the actual video memory, things can
be really el-stinko.

>Newer ones like the Video 7, Paradise, and upcoming ones from STB and
>Orchid are noticably better.  The issue of 8 and 16 bit cards is just
>noise as long as you're talking about 16 color VGA support.  16 bit cards
>show their worth when you move to a 256 color mode.  It makes a big
>difference here, with 16 bit cards running up to 2 times as fast as
>8 bit cards.  How do I know about this?  Well, you see, we've got a
>new server coming that will support 256 colors.  It's not as fast as
>the 16 color server, but it's reasonable, and for people who just have
>to have more colors, it's a low cost alternative.

Yep.

>> "X11R3" isn't known as being especially efficient either... R4 is supposed
>> to be much better, but I haven't had the chance to play with it yet (there's
>>this little thing called a server that isn't there yet for 386 displays......)
>
>Much of the MIT R3 slowness was due to a lack of specific code for drawing
>on color displays.  R4 added new code to rectify this, but of course, we
>had already done this for VGA support, so you won't see the kind of dramatic
>improvement that is shown on something like a Sun between R3 and R4.

That I wasn't aware of, but I should have figured considering that you have
one of the best "X" implementations I've seen on a PC-based machine.

--
Karl Denninger (karl at ddsw1.MCS.COM, <well-connected>!ddsw1!karl)
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