From: Drew Eckhardt (drew@romeo.cs.colorado.edu)
Date: 03/31/93


From: drew@romeo.cs.colorado.edu (Drew Eckhardt)
Subject: Re: Is a 387 coprocessor worth it?
Date: Thu, 1 Apr 1993 04:46:23 GMT

In article <C4s1Ay.8o0@agora.rain.com> crittew@agora.rain.com (Walt Crittenden) writes:
>I'm running Linux on a 387DX-25 w/ 8Mb ram - I only use XWindows (twm)
>on a regular basis.

Is $200 for a 387DX chip worth it?

First :

$200 is over twice what you should be paying for a 387 - I've been
quoted ~$75 local for 33 Mhz Intel parts, and even the local Software Etc /
Walden Books has Cyrix 387DX's for $80.

Second :

The Xserver isn't very FPU intensive. Floating point is only used
for drawing arcs, scaling scaleable (ie Type-1) fonts. Many clients
don't do floating point either - just bitblts, etc.

So, installing a 387 would have a negligible effect on your X performance.

>If not, under what circumstances would it be?

If you ran floating point intensive software, like Finite Element
Analysis.

There are two things that slow down 'X' :

1. Memory - X is a memory hogg, even with shared libraries. If you don't
        have enough memory, X will swap to disk which can be 1000X slower
        than real memory.

        If you're paging when running 'X', buying more memory (if
        you have open slots, used 1M SIMMS can be found for ~$25 each)
        will speed things up significantly.

2. Brain dead graphics hardware. Some graphics boards are painfully
        slow. Text doesn't scroll on a Trident running the color X server,
        it crawls.

        If you have slow graphics hardware, and don't care about color
        try X386mono. It needs to shovel 1/8 the amount of data
        that the color server does, making things tolerable.

        If you have slow graphics hardware, you should consider
        buying a faster video board. Generic TSENG ET4000 boards
        can be found for < $100, even faster S3 boards are available
        in the $200 range.
        

-- 
Boycott USL/Novell for their absurd anti-BSDI lawsuit. | Drew Eckhardt
Condemn Colorado for Amendment Two.                    | drew@cs.Colorado.EDU
Use Linux, the fast, flexible, and free 386 unix       |