VOGONS


Reply 20 of 25, by BeginnerGuy

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konc wrote:
I need to get one of those :lol: OK just joking, I see you wrote the other way around the "AT that you can drop it down to XT s […]
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BeginnerGuy wrote:

XT 286 8MHz is a total must...

I need to get one of those 🤣 OK just joking, I see you wrote the other way around the "AT that you can drop it down to XT speed".
Although that's not entirely true for the very few 4.77MHz things, so if you really need to cover "all", you need a 4.77MHz capable XT and a CGA for the correct colors.
The dedicated CGA PC is far more important in my opinion than the XT. How else can you get the correct CGA colors? That's why for me a single PC is not enough, no matter what speed you can bring it down to. Of course this does not apply for most people who maybe haven't ever seen a true CGA and don't have any interest in such old games.

uh oh, I'm beginning to forget which IBM is which now. AT is also a 286? What's the difference between AT and XT?? And what did we call the original 8088 model? The "PC"?

Didn't the 8mhz 286 models have a turbo to drop down to 4.77mhz mode (that's what I meant in my backwards comment)? Or was that still too fast due to architectural enhancements? Or only clones had turbo switches?

I still want an IBM with a 286 + EGA + IBM enhanced color, exactly how I remember them in my fading memories 😊

Sup. I like computers. Are you a computer?

Reply 21 of 25, by alvaro84

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BeginnerGuy wrote:

Didn't the 8mhz 286 models have a turbo to drop down to 4.77mhz mode (that's what I meant in my backwards comment)? Or was that still too fast due to architectural enhancements? Or only clones had turbo switches?

A 286 was (is) like 2-3 times faster than a 8088 of the same clock rate so yes, if a game is really speed sensitive it can be a problem.

But it's not really my field of expertise 😊

(I'm now researching the absolute other end of the DOS spectrum, Tualatins and Palominos and Northwoods that still have access to a properly working ISA bus. Of course they're completely useless for speed sensitive software.)

Shame on us, doomed from the start
May God have mercy on our dirty little hearts

Reply 23 of 25, by AvalonH

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Get a 440bx board, the last mainstream board to still include an ISA slot. I use one with a p3-500 +sb16/awe32 isa and it covers all DOS games quite well. Disabling L2 cache and setting the bus to 33mhz slows it down to a 386dx level.

The problem I have is not actually old games from pre 1988 that run too fast (so far every one I have tried runs normal and the few that don't work at the correct speed with the L2 disabled) but modern SVGA Dos protected mode games from 94-98 that are still too slow even with a p3-500. Games like 'Grand Prix 2' need a P3-900mhz to run full speed with all the detail turned on around Monaco. Also Nascar Racing etc.

Reply 24 of 25, by dionb

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AvalonH wrote:

Get a 440bx board, the last mainstream board to still include an ISA slot. I use one with a p3-500 +sb16/awe32 isa and it covers all DOS games quite well. Disabling L2 cache and setting the bus to 33mhz slows it down to a 386dx level.

BX boards are the Mercedes W123 of the computer world - reliable and usable on a daily basis far, far beyond any normal design expectation, so that's sound advice. However it's by no means true that BX boards were the last mainstream ones with ISA slots. Most early Socket A boards and a surprising number of i845 and i850-based Pentium 4 boards also has at least a single ISA slot. That said, I wouldn't recommend them over a decent BX board. I don't trust the reliability of So478 systems, due to the higher power draw they tend to make more noise, and there's more chance of hardware with no DOS support and less chance of a full complement of the old legacy ports, so BX is pretty unmatched here, particularly if you can find something with Tualatin BIOS support and a lot of ISA, like the Asus P2B rev 1.12.

Reply 25 of 25, by Ivanov

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So I bought an Asus TX97-XE motherboard, thats 430TX chipset, and now I can't decide on CPU to use. I'm debating between a Pentium 200 classic and a Pentium 233 MMX, both have selectable multipliers, with the lowest multiplier being 1.5x for the p200 and 2.0x for the p233, which combined with the motherboard's FSB range of 50, 55, 60, 66 and 75mhz, would mean the minimum I can bring the p200 to is 75mhz, while for the p233mmx it would be 100mhz, of course it can additionally be slowed down further by disabling the caches, but idk exactly how much that would be.

I pretty much gave up on 8088/8086 and 286 compatibility here because the games that would require those would also require CGA/EGA card and monitor to display correctly, besides most of them are not really good enough to be worth playing anyways. So I'm more interested in being compatible with the games that would require a 386 or a 486 to run correctly, so I'd like to know what speed pentium (with caches disabled) would more accurately emulate those, would 100mhz p233mmx be slow enough, so I can safely go with that and have extra speed for late DOS games, or do I still need to go below 100mhz so the p200 would be the one to go for after all?