Can you give an example where a faster VGA card breaks a game? I'm only aware of CPU speed doing something like that.

Kahenraz wrote on 2026-04-14, 23:00:

Can you give an example where a faster VGA card breaks a game? I'm only aware of CPU speed doing something like that.

This is an esoteric scenario, but I've been testing an ISA video card (Diamond Speedstar VGA) on a Pentium 4 setup (2.0GHz Northbridge).

Descent is a speed-sensitive game that requires Pentium-era performance to run correctly. What I discovered is that running it on a Pentium 4 with no CPU throttling but using this ISA video card makes it perfectly playable. It's like playing on a Pentium or fast 486 setup.

Similarly I tried Warcraft. On an AGP card, the water animation palette cycling is extremely fast. On this ISA card, the animation is much slower, again similar to a fast 486 or Pentium.

This is making me consider the possibilities of a multi-GPU setup where ISA video cards are used for speed throttling alongside traditional CPU methods.

Part of the reason I am interested in performance tuning of the ISA card itself, is to better control potential speed. For example, on the Diamond Speedstar VGA it has some dip switches that control memory speed (turbo and regular setting). There is a minor performance between each setting. Not enough for a major difference, but I'm curious as to how much video card performance can impact tuning games to specific performance levels.

keropi wrote on 2026-04-14, 21:20:

the hardware config for the 5434 is the fastest possible - since the drams are way faster than what the chip can use, 35ns IIRC
perhaps cirrus tools like mclk can be used for slower clocks but ultimately it will the cpu that will break the games not the vga IMHO

Interestingly I discovered that I can use an ISA video card on a Pentium 4 and a game like Decent is perfectly playable with no CPU throttling.

I'm not sure if it's the video card itself or possibly in combination with the ISA bus (and PCI-ISA bridge on the motherboard). But it's kinda fascinating to me to see what is possible with different methods to try to play speed sensitive games.

Shponglefan wrote on 2026-04-14, 23:38:

Interestingly I discovered that I can use an ISA video card on a Pentium 4 and a game like Decent is perfectly playable with no CPU throttling.

I'm not sure if it's the video card itself or possibly in combination with the ISA bus (and PCI-ISA bridge on the motherboard). But it's kinda fascinating to me to see what is possible with different methods to try to play speed sensitive games.

In the case of Descent, it can self adjust the speed of the game (with caveats) up to 150fps. If the ISA card slows down on screen rendering to less than 150fps it will feel like normal speed. The caveat is the homing missle turning radius gets smaller at higher framerates even though the rest of the game runs at normal speed. In other speed sensitive games they have less self-correcting ability and so even going from 30 to 60fps would make it unplayable.

Would it be possible to add an Eprom-socket for XT-IDE, or to implememt an Eeprom for that, please? 🥺

M240 wrote on 2026-04-15, 14:48:

Would it be possible to add an Eprom-socket for XT-IDE, or to implememt an Eeprom for that, please? 🥺

there is a plcc32 socket for this reason - controlled by the realtek chip
it is made for a 010-style chip (29F010 , 39SF010 etc)
it's the empty socket on the photo - it's the prototype we just received and assembled 😁

Wow! Expect me to order one when they are available. As always, an absolutly stunning card 😯👍 🥰

@Keropi
I was thinking while looking at the prototype:

Given the theoretical capacity of the 16-bit ISA bus (about 8MB/sec), how will the card perform at full capacity?

That is, will it be possible to use all the components together in a Windows environment? (I imagine playing solitarie while listening to a MIDI file
and transferring a file to the computer from the home network.)

And under DOS, will a theoretical bus capacity of 8MB/sec be enough to handle audio and video in games?

Thank you for your time 🤗

It will behave the same as if you had 4 different ISA cards in your system, ISA bus does not care if you use 4 slots or one.
Essentially it is no different than having a system with an ISA riser and you start populating it's slots.

What is the jack on the bottom for? It looks like either USB or Ethernet. I can't tell from this angle. Or maybe a mini DIN connector.

keropi wrote on 2026-04-15, 20:58:

It will behave the same as if you had 4 different ISA cards in your system, ISA bus does not care if you use 4 slots or one.
Essentially it is no different than having a system with an ISA riser and you start populating it's slots.

Thank you so much for your reply, it cleared up my doubts 🤗

Kahenraz wrote on 2026-04-15, 22:05:

What is the jack on the bottom for? It looks like either USB or Ethernet. I can't tell from this angle. Or maybe a mini DIN connector.

It is an ethernet one

What is it for? Networking?

Another killer device coming up...count me up to buy one! 😀

Boohyaka wrote on 2026-04-16, 09:22:

Another killer device coming up...count me up to buy one! 😀

Same!

Insert "take my money meme gif"

Kahenraz wrote on 2026-04-16, 08:36:

What is it for? Networking?

Yes the ethernet jack is for networking, it's a combo card

I lack the knowhow and am NOT demanding (please do not confuse this as such). My chime-in today is just that I had been bouncing this sort of idea already, albeit in PCI rather than ISA form. The networking and MIDI capabilities are obvious and generally correspond.

For graphics, I like a Tseng chipset for Michael Jordan in Flight (a unique game that supports only a select handful of proprietary SVGA standards from the pre-VESA days) and the ability to run stock Windows 3.0 in ultra resolution. MIDI can be anything, though I particularly like how Yamaha XG is in certain titles (why I have gone for a YMF card, not because it also happens to have genuine OPL3). For digital sound there is a sort of "Super" Gravis Ultrasound: Ensoniq SoundScape, whose 16-bit capabilities (which are, in certain games, better than GUS or Sound Blaster 16) remained fully supported in the AudioPCI line which is still commonly found and cheap.

Anyway, it is one thing to clone desirable vintage cards but another to essentially build something new. Efforts like these keep our retro experiences alive like the form they used to be a while longer, and that is something to be grateful for. I know everything I listed in the last paragraph is already capable of being done via emulation, but I also know none of us would be here except that emulation just isn't quite the same.

Was there any consideration given to supporting digital output for LCDs? This is the only area that I feel could be improved. I have mixed results with VGA on my flat panels.

it looks very good on the few lcd screens we have here but ofcourse YMMV ...
it's not always the vga card to blame , the issue also lies with the flat panel controller not sampling good enough (and you get the jailbars because of this)
these chips were made back in the crt era where this issue did not exist , we have done our best for the output and will tweak it a little more for extra sharpness in 1024 and upwards resolutions

I would assume with the feature connector, using something like a CRT Terminator could be an option for getting digital out?