Doom will not run well on 25MHz 486, it just needs a better CPU. Preferably a DX2, if you have an upgrade socket you could put DX2-50 in there and that would be a massive difference. Also, your VGA might be limiting performance, depending how it's connected to the rest of the system. Run some DOS benchmarks (like 3DBench) to get some idea.

As for floppies, perhaps you could use a floppy drive emulator of some kind? I perfer to use floppies for the feel but then again I do have a USB 3.5" drive that works on Windows 10.

It sounds like you already have everything working. DOS didn't have drivers like you are thinking about them for Windows. Since games are running and you have sound you are there. CDROM and mouse are the common drivers most people need to install, some sound cards require a separate program, on others you configure jumpers on the card itself and it runs without anything else.

As Deunan mentioned with Doom a 486 SX 25Mhz is the low end of the of the platform and many games want a DX 33, while others need a DX2 66 to run well. Unless your motherboard can support a different CPU you're probably stuck at 386 and older games.

For transferring data from/to this machine i highly recommend getting a network card. Then you can use normal file shares in win3.11 (works with 98, XP, and 8.1 at least) to copy data around. Just mind the 8.3 naming limitation, win98 handled this automatically but win8.1 will be very puzzled when the machine on the other end refuses files with too long names.

Alternatively, for plain DOS, i can also highly recommend EtherDFS which is easy to set up assuming you have a linux box somewhere (a spare RPi will do for example). Common gotcha: Make sure all file names are lowercase on the linux side otherwise the DOS side will see them but fail to open them.

For setting up HDDs and making it recognize the full capacity use EZ-drive:

(make a floppy bootable, put this on it, boot from it, and run ez.exe)

There are others but this is imho the best of the bunch.
For machines that recognize the first ~500MB make a FAT16 partition of 500 MB for DOS, win3.11 and the usual programs you really need. That space will be enough. Then make another partition that takes as much space as possible.
It's better to use the DOS 7.1 (instead of 6.22) china DOS union release because that supports fat32 natively and runs on anything 386+. So your best bet would be 500+7500MB partitions for formatting the SD card. Or maybe 500(fat16)+1500(fat16)+the rest(fat32).
If you plan to use 3.11: it's not great on FAT32, don't do that. There's also a patch for win3.11 that fixes a few bugs with DOS 7.1, forgot what it was, if you happen to need it let me know and i'll try to dig it up.

If you had a 486 of about 66 to 80 mhz and internet connectivity you could go as far as playing online mp3 streams and stuff, but sadly anything slower than that is impractical. Still, it's fun.

EDIT: I've tried to setup retro machines using VMs but most of the time it turned out to not work out quite right. Nowadays my approach is to have a few floppies with some things to get started (DOS 7.1 install 1+2, EZ-drive with a patched windows ME fdisk, a regular 6.22 boot floppy with some utils just in case, and one i make specifically for each machine with a packet driver for the network card and EtherDFS).
So it's definitely worth to have some floppies at hand if you find some in a trash pile or something.

Then it's just partitioning, formatting, installing DOS, setting up EtherDFS and connecting to my NAS (which runs the server), and from there pull everything else i need.
That setup even works for a 286 (which is the lowest-spec machine i own), but i guess the hard part is finding a network card. 3com 3c509 is my fav so far.

Thanks for the quick replies!

Deunan wrote on 2021-05-31, 21:35:

Doom will not run well on 25MHz 486, it just needs a better CPU. Preferably a DX2, if you have an upgrade socket you could put DX2-50 in there and that would be a massive difference. Also, your VGA might be limiting performance, depending how it's connected to the rest of the system. Run some DOS benchmarks (like 3DBench) to get some idea.

As for floppies, perhaps you could use a floppy drive emulator of some kind? I perfer to use floppies for the feel but then again I do have a USB 3.5" drive that works on Windows 10.

I wanted to run DOOM for the gimmick, but it's a little sad it will never be fully playable. I will take a look at a floppy emulator, this will probably save my day.

SScorpio wrote on 2021-06-01, 00:53:

It sounds like you already have everything working. DOS didn't have drivers like you are thinking about them for Windows. Since games are running and you have sound you are there. CDROM and mouse are the common drivers most people need to install, some sound cards require a separate program, on others you configure jumpers on the card itself and it runs without anything else.

As Deunan mentioned with Doom a 486 SX 25Mhz is the low end of the of the platform and many games want a DX 33, while others need a DX2 66 to run well. Unless your motherboard can support a different CPU you're probably stuck at 386 and older games.

The thing is my Motherboard, as I understand, has a Low Insertion Force (LIF) socket, so I don't know if changing CPUs is going to be as easy as other MBs... I will attach you an image and maybe you can tell me if it's worth it.

Thanks about the driver issue. As far as I understand, you mainly check the jumpers and if it works, it works, right?

fgenesis wrote on 2021-06-01, 01:57:

For transferring data from/to this machine i highly recommend getting a network card. Then you can use normal file shares in win […]
Show full quote

For transferring data from/to this machine i highly recommend getting a network card. Then you can use normal file shares in win3.11 (works with 98, XP, and 8.1 at least) to copy data around. Just mind the 8.3 naming limitation, win98 handled this automatically but win8.1 will be very puzzled when the machine on the other end refuses files with too long names.

Alternatively, for plain DOS, i can also highly recommend EtherDFS which is easy to set up assuming you have a linux box somewhere (a spare RPi will do for example). Common gotcha: Make sure all file names are lowercase on the linux side otherwise the DOS side will see them but fail to open them.

For setting up HDDs and making it recognize the full capacity use EZ-drive:

(make a floppy bootable, put this on it, boot from it, and run ez.exe)

There are others but this is imho the best of the bunch.
For machines that recognize the first ~500MB make a FAT16 partition of 500 MB for DOS, win3.11 and the usual programs you really need. That space will be enough. Then make another partition that takes as much space as possible.
It's better to use the DOS 7.1 (instead of 6.22) china DOS union release because that supports fat32 natively and runs on anything 386+. So your best bet would be 500+7500MB partitions for formatting the SD card. Or maybe 500(fat16)+1500(fat16)+the rest(fat32).
If you plan to use 3.11: it's not great on FAT32, don't do that. There's also a patch for win3.11 that fixes a few bugs with DOS 7.1, forgot what it was, if you happen to need it let me know and i'll try to dig it up.

If you had a 486 of about 66 to 80 mhz and internet connectivity you could go as far as playing online mp3 streams and stuff, but sadly anything slower than that is impractical. Still, it's fun.

EDIT: I've tried to setup retro machines using VMs but most of the time it turned out to not work out quite right. Nowadays my approach is to have a few floppies with some things to get started (DOS 7.1 install 1+2, EZ-drive with a patched windows ME fdisk, a regular 6.22 boot floppy with some utils just in case, and one i make specifically for each machine with a packet driver for the network card and EtherDFS).
So it's definitely worth to have some floppies at hand if you find some in a trash pile or something.

Then it's just partitioning, formatting, installing DOS, setting up EtherDFS and connecting to my NAS (which runs the server), and from there pull everything else i need.
That setup even works for a 286 (which is the lowest-spec machine i own), but i guess the hard part is finding a network card. 3com 3c509 is my fav so far.

I bought some network cards some weeks ago with the idea to do something like that. I will take a look at what you told me and see what comes after that.

You can certainly change CPU's on a LIF socket - you just have to be patient and take it slowly, easing out each side a little bit at a time. The main question is whether your board has support for different bus speeds and/or DX/DX2/DX4 processors.

Finding the model number of the motherboard and looking up the details on http://www.win3x.org/uh19/motherboard/search would be a good start.

I would be surprised if it didn't support at least DX and DX2 processors.

Kinoli wrote on 2021-06-01, 07:45:

The thing is my Motherboard, as I understand, has a Low Insertion Force (LIF) socket, so I don't know if changing CPUs is going to be as easy as other MBs... I will attach you an image and maybe you can tell me if it's worth it.
(...)
As far as I understand, you mainly check the jumpers and if it works, it works, right?

Unless that CPU is soldered to the mobo (I've never seen a PGA 486 soldered, not in a PC anyway, but I have seen PGA 386DX soldered) it can be removed. You will need some decent flat screwdriver with at least 1cm wide blade. Put that in between CPU and socket and pry/turn a bit, then move to next spot. Not all sides will have access but 2 opposite ones is enough to get the job done. Just don't try to lift the very corners, you could break them off (plus the corner pins have stoppers on them, you don't want that damaged either). In general you care more about the socket than CPU though, that is cheap enough and can be replaced easily. The first removal of a CPU that has never been taken out is pretty tough, then it gets easier and you also have more experience.

Investigate the mobo and jumpers. It should be possible to set it to 33MHz and DX CPU, then you can put in that or DX2-66. You can always put in a faster CPU but unless you can change the mobo clock then the CPU will only work at current 25MHz. In other words, if you put in DX2-66 and keep the clock you will get a DX2-50 instead, also not bad if there is no other choice and 66MHz CPUs are usually easier to come by than 50MHz ones, at least were I live.
If for some reason you can't switch the mobo from SX to DX 486 then there's also SX2-66 chips out there. If you just put a DX2 anyway it should work, mostly, but might not in certain situations - depends on the mobo. So jumpering the mobo correctly is pretty important.

EDIT: Oh and 3 more things, do pay attention to pin 1 corner, use current photo if the socket is not well marked. The new CPU might require a bit of pressure to fully get in, preferably put something under the socket to avoid bending PCB too much. Lastly, an SX-25 can run with no heatsink or active cooling but a DX2 (or SX2) definitely need at least a heatsink. Preferably also slap some fan on that, I even use cotton thread as mounting mechanism for heatsink and/or fan, power can be supplied from one of the HDD/floppy connectors. If the fan is 12V and can run on 5V, it will be enough for 486 CPU.

I'd also recommend the CPU upgrade
your SX lacks a FPU this is what's killing Dooms performance.

Why did you want to upgrade the Video card? I don't see much potential for upgrading performance by doing this?
Dos doesn't require drivers for video, And even Win3x doesn't benefit much over using the standard SVGA drivers.

chinny22 wrote on 2021-06-01, 10:20:

I'd also recommend the CPU upgrade
your SX lacks a FPU this is what's killing Dooms performance.

Doom only uses integer math, Quake was FPU heavy.

With respect to the CL 5428, it's a really good Dos gaming chip - I don't know if your board has it connected via ISA or local bus; if it's ISA and you have a VLB/PCI slot free, then a VLB/PCI card would be a good upgrade (the ISA bus is a big bottleneck for games like Doom that push a lot of pixel data). If, however it's it's already a VLB connection (either in a slot or embedded on the motherboard itself) then you'll not gain much for changing to another card, certainly not for Dos games.

chinny22 wrote on 2021-06-01, 10:20:

I'd also recommend the CPU upgrade your SX lacks a FPU this is what's killing Dooms performance. […]
Show full quote

I'd also recommend the CPU upgrade
your SX lacks a FPU this is what's killing Dooms performance.

Why did you want to upgrade the Video card? I don't see much potential for upgrading performance by doing this?
Dos doesn't require drivers for video, And even Win3x doesn't benefit much over using the standard SVGA drivers.

Doom does not make use of an FPU at all. A 25MHz 486 is just a tad too slow for Doom, you really want a DX2/66 to start getting playable and in order to hit the 35fps framecap constantly, you want DX4/100 and up.

If the video card is wired using the ISA bus, it is certainly not ideal for a 486. Although I fear this may be your only choice, early 486 lacked VLB (and certainly PCI).

You may also wish to try FastDoom to gain additional performance without changing the look of the game and perhas tweak visuals to your liking to achieve even further performance boosts. It's pretty neat to say the least.

Thanks everyone again for the answers.

megatron-uk wrote on 2021-06-01, 09:49:

You can certainly change CPU's on a LIF socket - you just have to be patient and take it slowly, easing out each side a little bit at a time. The main question is whether your board has support for different bus speeds and/or DX/DX2/DX4 processors.

Finding the model number of the motherboard and looking up the details on http://www.win3x.org/uh19/motherboard/search would be a good start.

I would be surprised if it didn't support at least DX and DX2 processors.

This page absolutely saved me! I found the documentation of my mobo! Thanks!

Deunan wrote on 2021-06-01, 09:51:

Unless that CPU is soldered to the mobo (I've never seen a PGA 486 soldered, not in a PC anyway, but I have seen PGA 386DX solde […]
Show full quote

Kinoli wrote on 2021-06-01, 07:45:

The thing is my Motherboard, as I understand, has a Low Insertion Force (LIF) socket, so I don't know if changing CPUs is going to be as easy as other MBs... I will attach you an image and maybe you can tell me if it's worth it.
(...)
As far as I understand, you mainly check the jumpers and if it works, it works, right?

Unless that CPU is soldered to the mobo (I've never seen a PGA 486 soldered, not in a PC anyway, but I have seen PGA 386DX soldered) it can be removed. You will need some decent flat screwdriver with at least 1cm wide blade. Put that in between CPU and socket and pry/turn a bit, then move to next spot. Not all sides will have access but 2 opposite ones is enough to get the job done. Just don't try to lift the very corners, you could break them off (plus the corner pins have stoppers on them, you don't want that damaged either). In general you care more about the socket than CPU though, that is cheap enough and can be replaced easily. The first removal of a CPU that has never been taken out is pretty tough, then it gets easier and you also have more experience.

Investigate the mobo and jumpers. It should be possible to set it to 33MHz and DX CPU, then you can put in that or DX2-66. You can always put in a faster CPU but unless you can change the mobo clock then the CPU will only work at current 25MHz. In other words, if you put in DX2-66 and keep the clock you will get a DX2-50 instead, also not bad if there is no other choice and 66MHz CPUs are usually easier to come by than 50MHz ones, at least were I live.
If for some reason you can't switch the mobo from SX to DX 486 then there's also SX2-66 chips out there. If you just put a DX2 anyway it should work, mostly, but might not in certain situations - depends on the mobo. So jumpering the mobo correctly is pretty important.

EDIT: Oh and 3 more things, do pay attention to pin 1 corner, use current photo if the socket is not well marked. The new CPU might require a bit of pressure to fully get in, preferably put something under the socket to avoid bending PCB too much. Lastly, an SX-25 can run with no heatsink or active cooling but a DX2 (or SX2) definitely need at least a heatsink. Preferably also slap some fan on that, I even use cotton thread as mounting mechanism for heatsink and/or fan, power can be supplied from one of the HDD/floppy connectors. If the fan is 12V and can run on 5V, it will be enough for 486 CPU.

It is exactly as you say. It is a LIF socket and upgradeable to an 486/DX2, so I'll probably get one of those with a heatsink and a fan. I will look at it to make sure everything stays cool as possible.

chinny22 wrote on 2021-06-01, 10:20:

I'd also recommend the CPU upgrade your SX lacks a FPU this is what's killing Dooms performance. […]
Show full quote

I'd also recommend the CPU upgrade
your SX lacks a FPU this is what's killing Dooms performance.

Why did you want to upgrade the Video card? I don't see much potential for upgrading performance by doing this?
Dos doesn't require drivers for video, And even Win3x doesn't benefit much over using the standard SVGA drivers.

I bought the external Video card because I did not see the onboard GPU, that's why 🤣

megatron-uk wrote on 2021-06-01, 10:34:

With respect to the CL 5428, it's a really good Dos gaming chip - I don't know if your board has it connected via ISA or local bus; if it's ISA and you have a VLB/PCI slot free, then a VLB/PCI card would be a good upgrade (the ISA bus is a big bottleneck for games like Doom that push a lot of pixel data). If, however it's it's already a VLB connection (either in a slot or embedded on the motherboard itself) then you'll not gain much for changing to another card, certainly not for Dos games.

The video card is soldered onboard, so I imagine it is via local bus? I only have ISA-16 slots, that's where my Sound Blaster Network adapter goes. If I can squeeze a little bit of performance out of the machine changing the CPU, I'll definitely do that.

Garrett W wrote on 2021-06-01, 10:38:

Doom does not make use of an FPU at all. A 25MHz 486 is just a tad too slow for Doom, you really want a DX2/66 to start getting […]
Show full quote

chinny22 wrote on 2021-06-01, 10:20:

I'd also recommend the CPU upgrade your SX lacks a FPU this is what's killing Dooms performance. […]
Show full quote

I'd also recommend the CPU upgrade
your SX lacks a FPU this is what's killing Dooms performance.

Why did you want to upgrade the Video card? I don't see much potential for upgrading performance by doing this?
Dos doesn't require drivers for video, And even Win3x doesn't benefit much over using the standard SVGA drivers.

Doom does not make use of an FPU at all. A 25MHz 486 is just a tad too slow for Doom, you really want a DX2/66 to start getting playable and in order to hit the 35fps framecap constantly, you want DX4/100 and up.

If the video card is wired using the ISA bus, it is certainly not ideal for a 486. Although I fear this may be your only choice, early 486 lacked VLB (and certainly PCI).

You may also wish to try FastDoom to gain additional performance without changing the look of the game and perhas tweak visuals to your liking to achieve even further performance boosts. It's pretty neat to say the least.

DOOM is more for the meme and less for playing it on this machine, altough if it's playable, I'll give it a try. I have some MS-DOS games I want to try and also I'll search for some more, probably from 1993 or before, because even with a 486/DX2, the CPU is not probably up to the task.

Kinoli wrote on 2021-06-01, 13:03:

megatron-uk wrote on 2021-06-01, 10:34:

With respect to the CL 5428, it's a really good Dos gaming chip - I don't know if your board has it connected via ISA or local bus; if it's ISA and you have a VLB/PCI slot free, then a VLB/PCI card would be a good upgrade (the ISA bus is a big bottleneck for games like Doom that push a lot of pixel data). If, however it's it's already a VLB connection (either in a slot or embedded on the motherboard itself) then you'll not gain much for changing to another card, certainly not for Dos games.

The video card is soldered onboard, so I imagine it is via local bus? I only have ISA-16 slots, that's where my Sound Blaster Network adapter goes. If I can squeeze a little bit of performance out of the machine changing the CPU, I'll definitely do that.

No, unfortunately that's not guaranteed. We'll have to take a look at the documentation and see how it is connected. My bet is that it is ISA, which would in turn make Doom run a lot worse and perhaps further explain your disappointment. I tried looking around with the model you provided, but I couldn't find it, are you sure it's the HP Vectra 486/25M? Could you take a couple of photos of the case as well as the internals, mainly the motherboard? That would help immensely.

If it's ISA, then it's a toss-up whether a different ISA card would make any noticeable difference. My testing shows negligible difference with an ISA ET4000AX and a similarly spec'ed ISA CL5428 with all things being equal (bus speeds, wait states, etc).

If it was a Realtek, Oak or similar low-end VGA chip on board then I'd say go for it - grab an ET4000 or Cirrus Logic. But I don't think it will make much difference here.

We forget a lot to mention the difference the implementation can make of various graphics chipsets. Some boards are horribly slow, even when the chipset is well thought of, for instance I didn't like the ET4000 for years, because I must have had a sucktastic one back in the day. Some implementations are particularly good, I believe the Orchid Kelvin 64 ISA for example crosses into low end PCI card territory. So anyway, try and look up to see what benchmarks are typical for your current chipset, if you're way off the pace, may as well get another board, but then look into which ones are better.

Video output quality is also important - I have a couple of ISA SVGA cards and some suffer from banding (or noise - I assume it comes from 12V line that is not loaded properly without mechanical HDD) on modern LCDs. Point is, on later systems (PCI, AGP) this is less of an issue and there are more decent cards to choose from. So you can always build a faster system in general if Doom or Quake is too slow. ISA-only mobo often require one to choose between speed and video quality. Not everyone can find, afford, or even want ET4000, and some of those can have poor output too.

Not to be odd man out but the 486sx25 is literally the only cpu that requires an overclock no one built an SX25 in the day and didn’t overclock.

If you have a cache less 486 motherboard and want a small speed boost overclock the FSB to 33mhz,
if your not worried about loosing data?
Try 40mhz or even 50mhz, you will need a heat sync but the speed boost is well worth $0

If your board has cache 33/40 is likely all you will get unless the board automatically drops cache timing

Good Luck

In '96 or so when SX25s were practically free and you could buy a DX33 for $5, me and a buddy or two would get SX25s and try to see how long it would take to kill them. Well they ran flaky without cooling at 50, but we had them looping doom demos for days at 40Mhz, no heatsink, got hot enough to be worrying, and kill one we never did. I think we just got bored of tying up motherboards with them.

rmay635703 wrote on 2021-06-01, 20:02:

Not to be odd man out but the 486sx25 is literally the only cpu that requires an overclock no one built an SX25 in the day and […]
Show full quote

Not to be odd man out but the 486sx25 is literally the only cpu that requires an overclock no one built an SX25 in the day and didn’t overclock.

If you have a cache less 486 motherboard and want a small speed boost overclock the FSB to 33mhz,
if your not worried about loosing data?
Try 40mhz or even 50mhz, you will need a heat sync but the speed boost is well worth $0

If your board has cache 33/40 is likely all you will get unless the board automatically drops cache timing

Good Luck

That's also a very good suggestion. 33 MHz is pretty much guaranteed, 40 less so as the RAM might not be up to the task.

BitWrangler wrote on 2021-06-01, 14:12:

We forget a lot to mention the difference the implementation can make of various graphics chipsets. Some boards are horribly slow, even when the chipset is well thought of, for instance I didn't like the ET4000 for years, because I must have had a sucktastic one back in the day. Some implementations are particularly good, I believe the Orchid Kelvin 64 ISA for example crosses into low end PCI card territory. So anyway, try and look up to see what benchmarks are typical for your current chipset, if you're way off the pace, may as well get another board, but then look into which ones are better.

All the reading I did back then indicated the ET4000 sucked for Dos but was great for Windows.