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From: simon@hpspwr.enet.dec.com (Curiosier and curiosier...)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Speeding up an XT
Message-ID: <16345@shlump.nac.dec.com>
Date: 15 Oct 90 14:52:50 GMT
Sender: newsdaemon@shlump.nac.dec.com
Organization: Digital Equipment Corporation
Lines: 41


In article <9010150903.AA09539@thep.lu.se>, magnus@THEP.LU.SE (Magnus Olsson) writes...
>I've heard about 80286 expanison boards that plug into an XT slot, for
>example something called the "Tiny Turbo", which are comparatively cheap.
>Of course, they won't turn my computer into an AT, but at least they'll
>speed it up a bit, and I assume I'll still be able to use my old
>peripherals. 
> 
>Does anybody out there have any experience with boards like this? Are they
>worth the price? How much faster do they make the XT? Is it still possible
>to switch back to the old 8088 processor (e.g. for copy-protected games
>that rely on 8088 timing)? Do they cooperate well with other XT expansion
>boards? 

I used to have a Tiny Turbo Xtra, a 12 MHz 286 to add to a 4.77/8 MHz 
XT.  At the time it was a good choice -- for about $280 I was able to 
speed up the system considerably.  For the home use it was enough.  The 
thing had an 8K fast processor cache to circumevent the I/O bottleneck.  Of 
course, it had its problems.  One of them was the fact that the hard 
with an XT controller was not capable of working with the increased CPU 
speed.  The disk was choking  -- the transfer rate fell from 225KB/sec 
to 95 KB/sec.  A few things had to be done:  1) Change the disk interleave 
factor from 3 to a new optimum 4; 2) Used controller BIOS ROM shadowing 
(RAMIT! program, available on request).  This combination increased the 
rate to a tolerable 170 Kb/sec.

All in all I should say that if all you can spend on the upgrade is $200
-300, an accelerator board may not be a bad thing.  You can switch back 
and forth between a 286 and an 8088 modes with a flip of a switch at the 
back of the PC.  I saw a regular Tiny Turbo (not Xtra) for 4.77 XT for 
around $200.  Unfortunately the idea that one can increase speed of a PC 
quickly lead me to spending even more bucks to buy a 386SX within six 
months :-)!

---------
Leo Simon			simon@pwrvax.enet.dec.com

Who is not liberal when young, does not have a heart.
Who is not conservative when old, does not have a brain.

						-- W. Churchill