[comp.sys.ibm.pc] '386 accelerator boards for PC/XTs

Bob-B@cup.portal.com (12/11/87)

I have been reading favorable reviews of '386 accelerator boards for the
PC/XT level machines.  These are not inexpensive boards and they raise a
question or two.  Our PC/XTs are 8 bit bus machines.  I assume that
imposes a significant limitation.  So what is the great benefit in
spending a thousand dollars on one of these '386 boards, especially
assuming one already has a '286 accelerator board installed?  I imagine
clock speed will increase with a '386 much like clock speed increased when
I installed an Orchid 286, but being able to boast a higher Norton SI
rating became passe rather quickly.  So now there are the '386 boards for
PC/XTs but I don't understand what 'performance' benefits I can expect to
realize from such a board.  Anyone care to shed some light?

czhj@vax1.UUCP (Ted Inoue) (12/12/87)

in article <1905@cup.portal.com>, Bob-B@cup.portal.com says:
> XPortal-User-Id: 1.1001.2401
> 
> I have been reading favorable reviews of '386 accelerator boards for the
> PC/XT level machines.  These are not inexpensive boards and they raise a
> question or two.

One thing to note is that many of these '386 upgrades for XT class machines
are in fact entire motherboard swaps.  For between $1500 and $2000, you can
get a so-called 'baby' 386 motherboard, that simply replaces your current
XT motherboard.  Hence you get an entire 386 system, with slots etc. that 
will be able to do anything that any other 386 system can do.

Warning:  make sure that your power supply is beefy enough to handle the
increased load.  I'm not sure of the exact specs, but if you start pumping
a system full of RAM and additional boards, you're going to kill an XT
power supply, ASAP.

-ted inoue

jpp@slxsys.specialix.co.uk (John Pettitt) (12/17/87)

In article <1905@cup.portal.com> Bob-B@cup.portal.com writes:
>I have been reading favorable reviews of '386 accelerator boards for the
>PC/XT level machines.  These are not inexpensive boards and they raise a
>question or two.  Our PC/XTs are 8 bit bus machines.  I assume that
>imposes a significant limitation. 

It depends on the design of the 386 card.  If it is an emulating
card (that it it uses the 386 as a super 8088) it will be limited
buy the 8 bit data path.  If it is a co-processing card (Like
the Applied Reasoning PC-Elevator) with its own 32 bit ram it
should not be bus limited.

>				 So what is the great benefit in
>spending a thousand dollars on one of these '386 boards, especially
>assuming one already has a '286 accelerator board installed?  I imagine
>clock speed will increase with a '386 much like clock speed increased when
>I installed an Orchid 286, but being able to boast a higher Norton SI
>rating became passe rather quickly.  So now there are the '386 boards for
>PC/XTs but I don't understand what 'performance' benefits I can expect to
>realize from such a board.  Anyone care to shed some light?

The main reason for getting one of these cards is performance, 
mostly numeric processing. The 387 is far faster than the 8087 or 80287
and this, in dos applications, is where most of the benifits are seen.

The second reason for getting a 386 is functionality, the 386 chip
is a far better CPU and the 88/86/286 are.  New software products
like VP/ix, Windows 386 and OS/2 V2 (don't laugh it will arrive
sometime :-) are starting to use the 386 specific features. 

I summary: If you don't need the Virtual 86 mode and you don't
need a 387 you probably don't need a 386 yet.  In 2 years time
finding new 'PC' software may start to become hard as even now
a large amount of new products need at least an AT then you will
need a 386.


-- 
John Pettitt			UUCP   :{backbone}!mcvax!ukc!pyrltd!slxsys!jpp	
Specialix Systems		Domain :jpp%slxsys@pyra.co.uk
London, UK.  (Where else ? :-)  Voice  : +44 1 398 9422 (GMT)
rn: core dumped