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Do 486 or early Pentium class machines support CGA/EGA video cards?

Benson86

Benson86

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I've seen some conflicting info on my research. I'm limited on space and it would be nice to just have one main machine that could drive my mono/CGA/EGA/VGA monitors. With a 486 machine would I be able to put in whatever video card to match whatever monitor I was wanting to use at that time? That would be super convenient but I've read pre VGA cards can be cranky in 486 or faster class machines is there any truth to that? I wish I had room for 3 PC setups but its just not realistic lol.
 
Pre-EGA video cards *should* work okay in at least most 486 era machines; slapping Hercules cards into servers was still a thing into the early 1990's, but there are wrinkles. It's not that unusual to find that really old CGA or mono cards that were intended to be sold with 4.77mhz XTs don't like running at 8mhz or faster. (I personally saw this when I tried using an original IBM MDA card as a second display in my 486/33; a newer Hercules clone did work. I did also briefly stuck a CGA card into that same 486 just our of curiosity.) By the time you get into the Pentium era you may find some PCI machines don't like working with ISA cards at all, while others will grudgingly accept a VGA card but draw the line there.

Keep in mind that card-edge connectors like ISA slots aren't really designed to be shuffled around a lot; it's not unusual for edge connectors to be rated for as few as 50 mating cycles. So if your plan is to play monitor roulette between games you will probably wear out your motherboard pretty quickly. Instead of swapping cards you might want to consider configuring a 486 class machine with one of those transitional-era VGA cards made by companies like ATI or Oak which have both VGA and legacy digital connectors on them, allowing you to switch between monitors by just flipping some DIP switches or running a software utility. These cards performance-wise tend to be kind of mediocre compared to the best VGA has to offer, but they should do fine for the pre-VGA software and an acceptable job otherwise as long as you stay away from high-res/color SVGA modes.
 
Eudimorphodon said:
Pre-EGA video cards *should* work okay in at least most 486 era machines; slapping Hercules cards into servers was still a thing into the early 1990's, but there are wrinkles. It's not that unusual to find that really old CGA or mono cards that were intended to be sold with 4.77mhz XTs don't like running at 8mhz or faster. (I personally saw this when I tried using an original IBM MDA card as a second display in my 486/33; a newer Hercules clone did work. I did also briefly stuck a CGA card into that same 486 just our of curiosity.) By the time you get into the Pentium era you may find some PCI machines don't like working with ISA cards at all, while others will grudgingly accept a VGA card but draw the line there.

Keep in mind that card-edge connectors like ISA slots aren't really designed to be shuffled around a lot; it's not unusual for edge connectors to be rated for as few as 50 mating cycles. So if your plan is to play monitor roulette between games you will probably wear out your motherboard pretty quickly. Instead of swapping cards you might want to consider configuring a 486 class machine with one of those transitional-era VGA cards made by companies like ATI or Oak which have both VGA and legacy digital connectors on them, allowing you to switch between monitors by just flipping some DIP switches or running a software utility. These cards performance-wise tend to be kind of mediocre compared to the best VGA has to offer, but they should do fine for the pre-VGA software and an acceptable job otherwise as long as you stay away from high-res/color SVGA modes.
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Interesting, I didnt think about the slot wear but thats a good point. 486 seems like the best middle ground for what I want to build. I've been looking at the ATI Wonder type cards because they seem to do most of what I would want. I'm not looking at playing any VGA titles newer than mid 90's. Anything newer than that and I have a G4 Mac or a modern PC that can do it better anyway. Is it possible to run more than one video card? Do any Hercules cards support composite mono? Or is it pretty much only CGA that does composite out?
 
I have tested a Pentium 100 PCI/ISA motherboard with a Compaq CGA card from my Portable II and it works, it just complains about the switch settings being incorrect, but all utilities/programs see standard CGA video.
 
Benson86 said:
Do any Hercules cards support composite mono? Or is it pretty much only CGA that does composite out?
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Nope. Possibly you might find a dual-mode card (IE, one that does both CGA *and* Hercules) that also has a composite port, but I'll bet you a shiny nickel that it won't do composite color accurate to the way that an original CGA card does. And it also won't be happy co-existing with a VGA card in CGA mode. MDA/Hercules *can* coexist with VGA, but there are asterisks there. Among other things it'll prevent you from using 16 bit RAM access on a VGA card so equipped because of obscure limitations in the ISA bus when mixing 8 and 16 bit cards.

A 486 really isn't a good platform if you really care about composite CGA games. Almost all the games where this is actually relevant are intended for XTs, and coincidentally (or not) also tend to be picky about CPU speed. Another thing you'll run into is a significant number of AT bus machines, especially faster ones, don't have a fully kosher 14.318Mhz clock signal on the ISA bus; it'll work well enough to drive monitor sync but, again, colorburst will be messed up. If this is a category of games you *really* want to see in their "full glory" I would suggest doing a separate machine for that. A 486 with a VGA card is fine for running most anything that's good on a 286 or later as long as you have a turbo switch, but XT games are kind of their own kettle of fish.
 
Eudimorphodon said:
Nope. Possibly you might find a dual-mode card (IE, one that does both CGA *and* Hercules) that also has a composite port, but I'll bet you a shiny nickel that it won't do composite color accurate to the way that an original CGA card does. And it also won't be happy co-existing with a VGA card in CGA mode. MDA/Hercules *can* coexist with VGA, but there are asterisks there. Among other things it'll prevent you from using 16 bit RAM access on a VGA card so equipped because of obscure limitations in the ISA bus when mixing 8 and 16 bit cards.

A 486 really isn't a good platform if you really care about composite CGA games. Almost all the games where this is actually relevant are intended for XTs, and coincidentally (or not) also tend to be picky about CPU speed. Another thing you'll run into is a significant number of AT bus machines, especially faster ones, don't have a fully kosher 14.318Mhz clock signal on the ISA bus; it'll work well enough to drive monitor sync but, again, colorburst will be messed up. If this is a category of games you *really* want to see in their "full glory" I would suggest doing a separate machine for that. A 486 with a VGA card is fine for running most anything that's good on a 286 or later as long as you have a turbo switch, but XT games are kind of their own kettle of fish.
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It sounds silly, but honestly the only reason I even want CGA composite is so I can output to my composite Mono Green Monitor to play text adventures, that's honestly it lol. I still have the Tandy 1000, I just haven't been able to get the composite working still, but the CGA/Tandy color works well. Was thinking about selling it off and trying to get something that could "do it all" sort a speak. 90% use for VGA/EGA games with an occasional text adventure on the mono monitor. But that may just not be practical.
 
If you don't care about color artifacting, there are plenty of VGA to composite adapters.
 
I ran a genuine IBM EGA card in a k6-2 450 under windows 98 using an old driver

I did it for fun to test some screens I had, seemed to work fine

Playing a full screen 320x200 AVI on the card was amusing
 
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