The following is the capture of a thread from CompuServe's TRS80PRO Forum
which deals with the extra 128K memory upgrade from Tandy. This file is
Copyright (C) 1991, CompuServe Information Service, An H&R Block Company,
All Rights Reserved.
--------------------------------------------------------------------------


Sb: #TL/2 Memory
Fm: David Zvi Lecin 73530,1144
To: ALL

I sent this message to Tandy's support personnel:


I have the Tandy TL/2.  My original setup was the CM-11 monitor, 640K RAM and
the extra 128K video memory.  When I upgraded to the VGA monitor/card, I was
told that the extra 128K would no longer be accessed by my computer, and that I
could remove the 4 chips.

Wrong.  When I removed the 4 chips, two things happened.  First, programs which
ran under DeskMate wouldn't run anymore.  I got a DOS error code for
insufficient memory.  Secondly, the speed of the graphics display (DeskMate,
PopUtil, etc.) was so slow that it was painful to sit and wait for the screen
to be built.  Re-installing the 4 chips corrected both problems.

Tandy personnel and private users continue to insist that the 4 chips are not
being accessed by my computer despite the experiences I have had with and
without the chips.  Could you PLEASE tell me exactly what the 4 chips do, and
is DeskMate continuing to access them despite the fact that I now have VGA
(Monitor VGM-300, Tandy Card)?

My experience with and without the 4 chips is PROOF that SOMETHING is
happening!

Thank you for your time and effort.

-------------------------------------------------------------------------

I received two replies:


RESPONSE 1

The way the Tandy 1000TL/2 system is designed, 16K of base memory is reserved
for video.  With the installation of the 128K upgrade kit, this memory is given
back as part of the available base memory.  Even with VGA installed, the system
functions this way.

Without the chips installed, the video is configured in the standard 16K of
memory before routing it to the VGA adapter card.  The dot resolution of VGA is
greater than the resolution of CGA, causing the video output to be slower.


RESPONSE 2

You are correct in that certain programs work best with 768K installed on the
main logic board of a Tandy 1000TL/2 system with a VGA adapter card installed. 
One such program is First Publisher.  As well, screen updates are slower with
VGA than with the onboard video output, although the difference with the 128K
upgrade has not been addressed.

Based on our tests, if the extra 128K is not in the system  the system will
allocate a minimum of 16k to video memory even with a seperate board installed.