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running 5x86 cpu in IBM 5150 with Inboard/386

As a side note, today I discovered, at least on the Vendex 888-XT running an Inboard that the RAM on the CPU board does nothing. When I say it does nothing, I mean nothing. Meaning, you can completely remove the system ram entirely and the inboard boots, has no memory gaps, functions completely normally. The entirety of the system RAM is taken over by the Inboard, at least on this machine.
 
chjmartin2 said:
As a side note, today I discovered, at least on the Vendex 888-XT running an Inboard that the RAM on the CPU board does nothing. When I say it does nothing, I mean nothing. Meaning, you can completely remove the system ram entirely and the inboard boots, has no memory gaps, functions completely normally. The entirety of the system RAM is taken over by the Inboard, at least on this machine.
Click to expand...
Normally you would have to leave the first page (64K) on the mainboard for compatibility. (There was DMA mentioned somewhere i think?).
The Inboard ram does indeed replace all the system memory once it is initialized.

-Jonas
 
stynx said:
Normally you would have to leave the first page (64K) on the mainboard for compatibility. (There was DMA mentioned somewhere i think?).
The Inboard ram does indeed replace all the system memory once it is initialized.

-Jonas
Click to expand...
Nobody was more surprised than me. Booted, ran software, ran windows - was shocking.
 
Regarding low memory transfer results:
I suspect that either register settings are not optimal or your cpu timings are off.
The Kingston module most likely uses buffers or a small cache to connect the two clock-domains (386-486).
This approach may result in missed clock-cycles since they do not align.
I don't know if synching the Inboard with the Kingston 486 is actually possible... maybe if you ran both from the same osc?

-Jonas
 
I have looked a bit for my dos-config but the XT with the inboard386 is currently out of order because the PSU had a smoking accident when we reached 36°C earlier this year...
The boot drive (SCSI2SD) took a hit and i can no longer access the data.
You may have to look up AMD register setup stuff yourself because i have not documented anything about the AMD5x86.
Maybe the AMD586 is easy to set up?

Anyways:
the Kingston 468Now! module seems to have a big chip on the PCB.
You can most likely do some config to this chip with the right program.
And even if you have successfully activated the cache/buffer on the Kingston module,
the AMD5x86 may need another tool for correct cache operation.

There was another Inboard 386 thread here on vcfed and/or vogons, where this whole upgrade mania stared.
Maybe you can find some more info on how to reach the best performance?

My own inboard 5x86 tests are on ice right now and i am tinkering with a Power Mac 200MP at the moment.
I also have the final version of an Apple II music card in the pipeline ... maybe some day...

-Jonas
 
Regarding the low memory throughput of the Kingston 486Now! module:
I have read through some documents and there seem to be switches on some models of the accelerator.
These switches configure mostly the wait-states for the accelerator to access the main memory.
Maybe there is something to test there?
 
stynx said:
Regarding the low memory throughput of the Kingston 486Now! module:
I have read through some documents and there seem to be switches on some models of the accelerator.
These switches configure mostly the wait-states for the accelerator to access the main memory.
Maybe there is something to test there?
Click to expand...
I didn’t see any switches on the board but will look closer.
 
chjmartin2 said:
I didn’t see any switches on the board but will look closer.
Click to expand...
Your version of the 486Now! might not have them.
This would mean that you can only tinker with the oscillator and software.
Based on the other boards, the module supports 16, 20 and 25 MHz 386 clock rate.
20-33 and 25-33 is very asynchronous and i suspect that there are wait-states involved to synch the two clocks by latching.
Maybe either the internal 486DX-cache is use for that, there are internal latches/a small cache on the 486Now! or maybe the 486 is clocked down whenever a bus-access is done...
The later was used in early accelerators (without cache) to facilitate timing-sensitive operations and is very slow (which would explain your low memory scores).

You should look into the options that the 486Now! enable-software offers.
Maybe there are soft switches or registers to manipulate?

-Jonas
 
stynx said:
Your version of the 486Now! might not have them.
This would mean that you can only tinker with the oscillator and software.
Based on the other boards, the module supports 16, 20 and 25 MHz 386 clock rate.
20-33 and 25-33 is very asynchronous and i suspect that there are wait-states involved to synch the two clocks by latching.
Maybe either the internal 486DX-cache is use for that, there are internal latches/a small cache on the 486Now! or maybe the 486 is clocked down whenever a bus-access is done...
The later was used in early accelerators (without cache) to facilitate timing-sensitive operations and is very slow (which would explain your low memory scores).

You should look into the options that the 486Now! enable-software offers.
Maybe there are soft switches or registers to manipulate?

-Jonas
Click to expand...
The 486Now will run with a 40 MHz oscillator, actually it will run with a 43 MHz oscillator and the Evergreen accepts the overclock. The Kingston software I have only allows me to enable cache at specific memory locations, no other options. I am going to try to swap the memory on the inboard. The big difference i noticed versus your setup is that the memory access time is 10 meg/sec versus what you show at 20 meg/sec. I am going to try to run 40 MHz oscillators in both. I would like to try to run on the same oscillator but not sure how that would work with wires going across from the inboard to the 486 now.
 
chjmartin2 said:
I would like to try to run on the same oscillator but not sure how that would work with wires going across from the inboard to the 486 now.
Click to expand...
You can solder a wire to the 486Now oscillator clock pin on the bottom and plug that wire into the clock pin on the inboard386 oscillator socket. I doubt, that this will change the memory throughput (a lot) but it is worth try.
 
stynx said:
You can solder a wire to the 486Now oscillator clock pin on the bottom and plug that wire into the clock pin on the inboard386 oscillator socket. I doubt, that this will change the memory throughput (a lot) but it is worth try.
Click to expand...
Matched 40 MHz oscillators didn't make a difference. You are getting close to 20 meg a second on memory access times and mine is half of that. I tried new RAM and that didn't make a difference either. I can only get my bus to run at 7.3MHz and you said you were closer to 8, going from 4.77 to 7 made a significant difference. I think the 486Now interposer has some kind of wait states added due to the on-board oscillator. I will try. When you say bottom, do you mean the bottom left pin to the bottom left pin?
 
IMG_2451.jpg

Finally. Finally. I think the highest Top Bench I have seen for an Inboard 386 in an XT was 95, but I could be mistaken and please correct me. So the above is what I achieved tonight, I will figure out how to fit the 4mb board in it tomorrow. Obviously I can't, run this inside the case as you can see my upgrade stack popping out of the top. The secret sauce was to swtich from a 486Now! to the Kyoto Turbo 486EX66.

Computer Base Model: Vendex 888-XT
Bus Clock: 20 Mhz / 3 = 6.67 MHz (8 Mhz doesn't work with my Inboard for some reason)
Inboard Clock: 41 MHz / 2 = 20.5 MHz Base CPU Clock
386 to 486: Kyoto Turbo 486EX66
Kyoto Clock Multiplier: 2X
Base Clock to 486: 41 Mhz
486 CPU on Kyoto: Evergreen Technologies 5x86
5x86 Multiplier: 4X
5x86 Internal Clock: 164 MHz

Topbench Score: 112


I can tell it is a speed demon. I got some garbled graphics on Wolfenstein which isn't a great sign. I did manage to play Epic Pinball and that was smooth as silk. I also used Inertia Player to play mods through PC Speaker and could run the scopes or the Fourier. Will try more tomorrow. I am tired.

Chris
 
chjmartin2 said:
View attachment 1265533

Finally. Finally. I think the highest Top Bench I have seen for an Inboard 386 in an XT was 95, but I could be mistaken and please correct me. So the above is what I achieved tonight, I will figure out how to fit the 4mb board in it tomorrow. Obviously I can't, run this inside the case as you can see my upgrade stack popping out of the top. The secret sauce was to swtich from a 486Now! to the Kyoto Turbo 486EX66.

Computer Base Model: Vendex 888-XT
Bus Clock: 20 Mhz / 3 = 6.67 MHz (8 Mhz doesn't work with my Inboard for some reason)
Inboard Clock: 41 MHz / 2 = 20.5 MHz Base CPU Clock
386 to 486: Kyoto Turbo 486EX66
Kyoto Clock Multiplier: 2X
Base Clock to 486: 41 Mhz
486 CPU on Kyoto: Evergreen Technologies 5x86
5x86 Multiplier: 4X
5x86 Internal Clock: 164 MHz

Topbench Score: 112


I can tell it is a speed demon. I got some garbled graphics on Wolfenstein which isn't a great sign. I did manage to play Epic Pinball and that was smooth as silk. I also used Inertia Player to play mods through PC Speaker and could run the scopes or the Fourier. Will try more tomorrow. I am tired.

Chris
Click to expand...
hello
nice result chjmartin2 :)
the Kyoto Clock Multiplier is build on chip: NB3N502 ??
NB3N502 looks like a usable chip in our setup.
/cimonvg
 
mtrahms said:
How did you get the keyboard working? Is that a side effect of the DOOM tech demo?
Click to expand...
hello
i don't know how Stynx did manage to enable keyboard in Doom, My demo ran automatically and then gave framerate numbers.
But perhaps Doom runs better on IBM5160 then the IBM5150?
Otherwise you should be able to run the game with mouse and joystick (i think - have not tried) on the IBM5150 :)
/cimonvg
 
Hi there!
This X article is from VCF West in 2021,

Can anyone tell me what this adapter & flat cable that connects the CPU accelerator to the Inboard is?
I have a Buffalo EUD-H0M and am considering putting it on my Inboard, but without such an adapter
I cannot put the lid on my PC. Is it possible to get one?
 

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mtrahms said:
How did you get the keyboard working? Is that a side effect of the DOOM tech demo?
Click to expand...
Many years ago you could load custom keyboard tsr to make things more compatible.

Seems like they usually were for early Tandy and PCJR systems though.

Oddly many later programs expected the keyboard and hard drive in AT locations which breaks functionality
 
stynx said:
There is still a lot of ways to go faster :)

Used Machine: PC XT (5160) with 8mhz bus, Inboard386 with clock-mod, Kingston 586 5V upgrade (x4 mode), 128k UMB, ET4000, SCSI (CF-HD, CD), 1.44mb floppy.

View attachment 1016097

View attachment 1016099

Doooooooooom :)

Aaaaand a bit faster now :) (no memory expansion though)
View attachment 1016100
View attachment 1016102
-Jonas
Click to expand...
What mod did you use to increase the bus speed to 8MHz? Did you use the PC-Sprint or Sergey's XT overclock?
 
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