Monster PPC512 Upgrade Project

[Eudimorphodon]

Pretty sure the fill rate on this card is only marginally faster than an etch-a-sketch

Just as an aside, what kind of speeds are you hoping for from a VGA card in this system? The service manual for this system says that the expansion bus runs at only 4Mhz and, of course, is 8 bits wide. The checkit benchmark in your other thread pegs the direct video CPS on the Realtek card as being about two and a half times faster than an XT, that actually seems remarkably good to me considering the bus bottleneck.

 

[orac81]

I have to say thats a pretty good home build. Where did you get the Trident VGA chip from? I have an old Trident ISA card in storage somewhere, 8900 I think.
Mainstream RAM prices have tripled in the last 6 months thanks to AI demand, but I'm suprised that effects the smaller stuff.
As for speed, some of the Amstrads had 8mhz V30s, I added one to mine back then. The little "racer" game I posted up a link to earlier is a useful test, it uses modex gfx hardware scrolling that works with most vga chipsets, even on a v30..

 

[RtechLab]

Just as an aside, what kind of speeds are you hoping for from a VGA card in this system? The service manual for this system says that the expansion bus runs at only 4Mhz and, of course, is 8 bits wide. The checkit benchmark in your other thread pegs the direct video CPS on the Realtek card as being about two and a half times faster than an XT, that actually seems remarkably good to me considering the bus bottleneck.

I dont have a lot to compare if I'm honest and not sure what I'm expecting but there are other issues with the card, it's defninateley not all that compatible whereas the TVGA aparently is much better. Also I can get these chips, the RealTek is an easier solution but its like rocking unicorn poo. It was also a subjective observation and after posting that and going back to some failry heavy GUI work I did on 286/386 I realised I'm expecting a little XT class to shift things way faster than it can.

 

[RtechLab]

I have to say thats a pretty good home build. Where did you get the Trident VGA chip from? I have an old Trident ISA card in storage somewhere, 8900 I think.
Mainstream RAM prices have tripled in the last 6 months thanks to AI demand, but I'm suprised that effects the smaller stuff.
As for speed, some of the Amstrads had 8mhz V30s, I added one to mine back then. The little "racer" game I posted up a link to earlier is a useful test, it uses modex gfx hardware scrolling that works with most vga chipsets, even on a v30..

Thank you.

The 8900 has an external RAMDAC IIRC and a higher external compnent count.

I took a punt on the chip and went for an AliExpress seller that seemed to specalise in aviation parts, paid more for the chip but reasoned the come back for counterfeit parts would be a lot higher for them. I think some of the DRAM is just getting rare now. When I re-roll this card I'm definateley going to switch to SMD ram, despite the pins theat TVGA9000 was easier to solder than the high density 74xx16xxx devices. The SMD dram can be pirated off many things including old SIMMs.

I quoted for a PC build today, same one I did a month ago and the memory prices have added £100 to the machine via SSD and RAM.

I'll grab that game soon as I have a working board and run it on both, RealTek and TVGA.

I'm debugging the XTMax card at the moment so I'm hoping to have HD support. I'm missing a DB25 for the second, PC104 board which is in transit somewhere. I managed to order DB25S rather than P

 

[Eudimorphodon]

whereas the TVGA aparently is much better.

FWIW, the TVGA 9000 had a reputation back in the day for being slower than frozen molasses, a reputation I would attest to because I had one in my ISA-only 486/33; it was fine for VGA-standard modes but its SVGA modes *were* extremely sluggish. That said, slow for a 486 probably doesn't mean much for a lesser machine. (And there's also the wrinkle that ISA-only 486s are always going to suffer compared to local bus systems, which started getting affordable about a month after the trigger got pulled on mine.) The limit is almost certainly going to be your bus and the CPU, not the card, when it comes to speed. Compatibility might be another kettle of fish.

It was also a subjective observation and after posting that and going back to some failry heavy GUI work I did on 286/386 I realised I'm expecting a little XT class to shift things way faster than it can.

I have an OAK VGA card in an even slower machine (7.16mhz V20, although in that machine the bus *does* run at the full speed of the CPU instead of a fixed 4mhz), and yeah, you need to set your expectations accordingly. The mono 640x480 mode can be genuinely useful for things like GEM applications, EGA paint programs and a few games can be fun, and GEOS runs *mind bogglingly* well (all things considered) even with an 800x600 16 color driver, but Windows is just self-flagellation. I completely don't understand the enthusiasm for slapping that on XTs.

 

[RtechLab]

FWIW, the TVGA 9000 had a reputation back in the day for being slower than frozen molasses, a reputation I would attest to because I had one in my ISA-only 486/33; it was fine for VGA-standard modes but its SVGA modes *were* extremely sluggish. That said, slow for a 486 probably doesn't mean much for a lesser machine. (And there's also the wrinkle that ISA-only 486s are always going to suffer compared to local bus systems, which started getting affordable about a month after the trigger got pulled on mine.) The limit is almost certainly going to be your bus and the CPU, not the card, when it comes to speed. Compatibility might be another kettle of fish.



I have an OAK VGA card in an even slower machine (7.16mhz V20, although in that machine the bus *does* run at the full speed of the CPU instead of a fixed 4mhz), and yeah, you need to set your expectations accordingly. The mono 640x480 mode can be genuinely useful for things like GEM applications, EGA paint programs and a few games can be fun, and GEOS runs *mind bogglingly* well (all things considered) even with an 800x600 16 color driver, but Windows is just self-flagellation. I completely don't understand the enthusiasm for slapping that on XTs.

I dont know why youd want Windows on there. I remebr having it on my 286 and at the same time I had an Amiga 3000 and I really couldnt see what Windows 3 offered. There's potentially bias at play because a lot of my hardware days where punctuated by some of the absolute horros Realtek produced later on in the socket 7 era.

 

[RtechLab]

Had a thought about interface board -=> Expansion board some more.
PC104 is handy, however making it work in that tight space is really a headache. Everyone using it will get that board sat on in different ways and once it's on, its on. A new method is required.

FPC, for that sise of a board, is a pain and expensive. It still carries the once its on, it's on issue. But the idea above is a good one.
So, halfway house. FFC ribbons are an off the shelf part as are the connectors. So new plan

The bus interface buffers will move onto the expansion board.
I'll make some .6mm or even small flat flex DB25/37 to FFC boards. These can be soldered on and left, they should be cheap enough to not worry about them staying behind and/or removable with gentle heat.
This also means this board will then be adaptable for other plaforms too with a different interface to FFC adapter.
Also it buys me some more board real estate.

 

[RetroHospital]

Speaking of ppc512 upgrade ; FYI something I've just tried and that doesn't seem to work is adding an PPC640 modem card into a ppc512
It loops in beeps and displays garbage on the screen (doesn't boot either obviously)

Maybe a BIOS issue, not sure the bios is different between the ppc512 and the ppc640
There doesn't seem to be an LK1-6 dedicated to modem problems, or even undocumented...

ANy ideas welcome

 

[Towmater]

I put an HDMI screen and a Disney Sound Source in a 640. It's a better experience, though I'd like to try the author's card as well.

 

[RtechLab]

This isnt dead. I have a "movie" team that goes out and works on films. They have been out on a big one for most of 2025 and they came back after Xmas with more kit than they took...a shipping container more. This precipitated and office move for the IT/Electronics haf of the business. I've been getting this going and been very busy on top, but, new workbenches are arriving next week and I'm hoping to be able to dedicate bench time to this in the next few weeks.

Re the Modem card, there should be no difference, the boards are the same from what I can see. The modem card does directly access some unbuffered address lines so it may be your card is bad.

R