NetNews Usenet Archive 1992 #30/NN_1992_30.iso/spool/sci/electron/20598

Text File | 1992-12-12 | 1.6 KB | 40 lines

Newsgroups: sci.electronics
Path: sparky!uunet!wupost!spool.mu.edu!agate!usenet.ins.cwru.edu!neoucom.edu!wtm
From: [e-mail] (Bill Mayhew)
Subject: Re: 486DX2 Crystals
Message-ID: <[e-mail]>
Organization: Northeastern Ohio Universities College of Medicine
References: <[e-mail]> <[e-mail]>
Date: Sun, 13 Dec 1992 02:38:19 GMT
Lines: 29

486DX2 chips use what is essentially a phase locked loop circuit
and 2* oscillator internal to the 486DX2 to synchronize internal
operations to the external environment running at regular speed.
As you might suspect, a clock doubled 25 -> 50 MHz 486DX2 performs
many benchmarks faster than a 33 MHz 486DX.  The clock doubling
inside the chip is offset by the fact that the system clock is only
25 MHz.

Several of the popular trade press publications have performed
comparisons.  There are some non-compute-bound scenarios where a
standard 486DX-33 outperforms a 486DX2-50 (file servers, for
instance).

The moral of the story is to know what you are you are buying and
to what the "MHz" rating refers.  The system clock or the CPU
doubled clock?

There are many other factors such as local bus video, memory
interleaving, secondary cache, EISA vs ISA vs MCA bus, disk system,
etc. that effect performance.  It is difficult to make a
performance evaluation of a system without performing a task mix
that models the actual working environment you intend for the
computer.


--
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: [phone]
[e-mail] (140.220.1.1)    146.580: N8WED