>So the Cyrix chip is faster than the Intel chip at the same clock, and it's
>way cheaper.  I can get a Cyrix 5x86-120 motherboard (with cpu) for $239,
>and the P5-120 is $449, almost twice as much.  Since I've got all the other
>parts in my junk box, that's a big difference.

I just re-read this...

You're comparing Pentium motherboard prices to 5x86 motherboard
prices.  You realize these are different generations of hardware?

A 5x86 is a "486-class" chip in the sense that it uses 486 hardware.
It has a 32-bit external data bus, and plugs into a 486 socket on a
486 motherboard.  It uses 486-generation support chips.

A Cyrix 5x86-120 is just about the maximum that hardware will ever do.
They could come out with a 5x86-200MHz, but it wouldn't add a whole
lot to performance, because you'd still be sucking data over a 32-bit
path at 5-6 times the bus speed (can you say bus saturation?), and
you'd be using slower 486-generation memory access support chips.

A Pentium has a 64-bit external data bus.  Modern Pentium motherboards
(like Triton-based ones) use more advanced memory access technology
like EDO RAM and Pipeline-Burst cache RAM, resulting in fewer wait
states per bus transaction.  You can move up to a multi-media 200MHz
Pentium some time in the future, with a decent motherboard, and expect
to see most of that added performance (64-bit bus; fewer wait states).

Simply put, a 120MHz Pentium motherboard will run significantly faster
than a 120MHz Cyrix or AMD 5x86, and it has a lot more potential for
growth.  If you're buying hardware brand new, you'd be a fool to
invest in 486 (5x86) hardware at this stage in the game.  You're just
buying dead-end technology.  IMHO, of course...

Now, one more thing I'd like to address while I'm on my soapbox. :-)
If you're going to buy a PCI motherboard, you might want to take a
good hard look at whether you can afford to go up to the next 33x MHz
(100MHz, 133MHz...) chip, rather than a 30x (120MHz, 150MHz...) chip.
The reason is: the memory bus runs at 66.7MHz on a 33x chip, and 60MHz
on a 30x chip (on a Pentium), making the PCI bus run at 33.3MHz or
30MHz, respectively.  If you have some really heavily I/O-based work,
a 100MHz system could potentially be faster than a 120MHz system
because of this, in some cases.  So, if you're already thinking about
120MHz, you might want to try to stretch the budget just a little bit
more and get a 133MHz chip.  On the other hand, if your work is
strictly compute-intensive, you might do OK with a 120MHz chip and a
slightly slower bus.

-----------------------------------------------------------------------------
  Michael L. VanLoon                                 michaelv@HeadCandy.com
        --<  Free your mind and your machine -- NetBSD free un*x  >--
    NetBSD working ports: 386+PC, Mac 68k, Amiga, Atari 68k, HP300, Sun3,
        Sun4/4c/4m, DEC MIPS, DEC Alpha, PC532, VAX, MVME68k, arm32...
    NetBSD ports in progress: PICA, others...

   Roll your own Internet access -- Seattle People's Internet cooperative.
                  If you're in the Seattle area, ask me how.
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