Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!iuvax!purdue!decwrl!sgi!tarolli
From: tarolli (Gary Tarolli)
Newsgroups: comp.sys.sgi
Subject: Re: windows
Summary: 4D vs. 2400T
Message-ID: <33058@sgi.SGI.COM>
Date: 17 May 89 20:40:20 GMT
References: <8905170942.aa09286@CAD.USNA.MIL>
Sender: daemon@sgi.SGI.COM
Organization: Silicon Graphics, Inc., Mountain View, CA
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There can be multiple reasons why a 4D machine is VISUALLY slower than
a 2400T.  One could be that the window manager is slowing things down,
either thru consuming CPU cylces or enough memory to cause extra paging.
Another could be because the 4D is performing "extra" unnecessary graphics,
in other words the port of the code created inefficiencies.  A classic
example is that the 4D machines smooth shade all polygons by default,
ie shademodel(GOURAUD) is the default.  This was for compatability sake.
If you are drawing flat polygons and forget to turn shademodel(FLAT) on,
performance is adversly effected.  Things like flight can run 5-10 times
slower.   There are other graphics routines that are slower on a 4D than
on a 2400T.  These are routines like depthcue() that are not usually called
often enough to matter, but once in a while you run across an application
that calls it excessively.  Because it was fast on a   2400T, no on cared,
but on the 4D it does a system call so......  The old curve demo had this
problem at first.

So, I am not convinced that the window manager is really making your 4D
visually slower than a 2400T.  When you are not paging, the window manager
has very little overhead and generally stays out of the way when you are doing
fast 3D graphics.  I would place my bets that your user code is not doing
what you expect on the 4D or is calling a routine that got slower.  Use
prof/pixie to detect these.