SYSTEM: IBM Cobalt-AT VLB, AMD 5x86, GS500 (full details below)
QUESTION: How to break this 32MB barrier?
 Win3.X will not boot IF RAM > 32MB .AND. GS500 video driver.
 (shows Windows splash screen then black, won't Ctrl-Alt-Del)

TESTING:
Original configuration works fine:
5x86 overclocked to 160MHz; Win3.1; RAM 16+4+4+4=28MB (all 70ns);
runs Captivator Pro functions and various multimedia encyclopaedias and
reference CDs.

Bought 16MB 60ns simm: new configuration 16+16=32MB works normally.

Configurations 16+16+4=36MB and 16+16+4+4=40MB
will boot to DOS, and boot to Windows if the _VGA_ driver selected,
but _never_ Windows with GrafixStar 500 driver.
It will run Encarta 95 video and sound in 40MB/VGA mode (16 colours).

Tried all the following (and most sensible combinations)
with no change: system _only_ sensitive to total RAM > 32MB
* swapped memory simm positions
* installed VideoLogic driver patches 103 105 111 213, then
* installed TSR patch 98 temporarily
* slowed CPU clock to 25/100MHz (see note below)
* reverted to built-in Blue Lightning processor 25/75MHz
* excluded video memory EMM386 X=A000-C7FF (only tried once)
* repeated tests (not CPU changes) with different 16MB 60ns simm
* upgraded from Win3.1 to WfWG (not reversible)
* upgraded GS500 driver to v1.2.1, then
* tried patches again
* emailed VideoLogic but they haven't replied yet

(Note: this doesn't seem to be a clock speed problem;
 the system is completely stable at 40/160MHz CPU, 8MHz ISA,
 and can be tuned further by shaving wait states and
 increasing ISA bus speed to 10 or 13.4MHz
 - showing better than 10% speed improvement in Wintune 2.0
 and 14/15 fps to 17.4 fps in XingMPEG Player diagnostic.
 It doesn't get twitchy until 16MHz ISA bus, when it
 boots into Windows OK but tends to hang unexpectedly.)

SUPPLEMENTARY QUESTION
Can I expect the GS500/Captivator Pro to work well in Win95?
I'm considering an upgrade to Win95 OSR2 soon and I may
install OSR2/Win3.11 dual boot just-in-case;
I would also like to install all available RAM to benefit Win95,
but it won't be practical to insert/remove RAM according to OS.

SYSTEM DETAILS
GrafixStar 500 2MB (SVGA BIOS v1.3), VMC Controller
Captivator Pro TV for VMC

Motherboard: IBM Cobalt-AT 486BL (VLB); Chipset: OPTi 82C499
CPU: IBM 486BL upgraded to Power Leap AMD 5x86-133
(normally run overclocked at 40/160MHz CPU, 8MHz ISA bus)

Cache: 256K; BIOS: MRBIOS; Memory: 28 -> 32 -> 40MB;

Sound: Wave Excel AV-501
VL-400  SCSI & IDE Cache (16MB) with Multi-I/O;
1GB Seagate IDE, several SCSI HD & CD-ROM

DOS 6.20; Windows 3.1 upgraded during testing to Win3.11 (WfWG)


Len Warner <[log in to unmask]> WWW Pager http://wwp.mirabilis.com/10120933