Windows 98SE supports FAT32 which gives you more storage space. DOS 6.22 uses FAT16 which is limited to 2GB partitions, though you can have several of those. In terms of compatibility, there shouldn't be any issues. Everything except for some sound card drivers that were made for actual DOS (mostly from Creative) will work fine under Win98SE.

Personally, I use two CF cards on my Pentium MMX: one with DOS 6.22 + Win3.11 and another one with Win95 OSR 2.1. To clarify, Win3.11 is there for purely nostalgic reasons , and the other card has Win95 mostly because I needed FAT32 and also because I already have Win98SE on my other rigs.

Win98SE and Win95 can boot straight into DOS from the boot (F8) menu, and a setting can be changed to always show this menu. That DOS version works just fine, I think there's a Creative driver installer or something that needs to be patched, but games will work fine.
Win95 could be faster on such a system but if it's only to transfer files I'd just go with 98.

I have Windows 98SE on my PIII and a single 80GB fat32 partition. Large partition support is the main reason to use the DOS bundled in Windows rather than 6.22. Instead of utilities being located in c:\dos they are in c:\windows. As suggested above I have boot menu always shown with options to start Windows, DOS with EMS and without EMS.

If your happy with this PC just for dos then you have 2 options.
Install Windows 3.11 (for Workgroups as this has networking built in)
This is what I did as it keeps the retro feel, and really for a dos gaming PC you don't have much other use for installing Windows.
BUT
Getting 3.11 to talk to later OS's can be tricky. Especially anything later then XP. and transfer speeds aren't great.

If you want the most reliable and hassle free you can use MTCP which is a ftp client for dos. file transfers are quicker and ftp is supported by just about anything with a network card.
http://www.brutman.com/mTCP/

If you want to start playing some early Win9x games and a Pentium MMX is definitely up to this Then I'd just install Win95 or Win98
Win95 is less CPU demanding and a good match or you can install Win98 lite which gives you Win95's performance with 98's improved stability.
In this case I wouldn't bother installing Dos 6.22 at all as "dos 7" that sits under Win9x is 99.9% compatible and includes benefits like Fat32 like mentioned above.
Win9x networking will still put of a fight if trying to connect to anything later then XP but it's still easer then 3.11
ftp is till an option as well.

PS dos does have a 3rd option, The dos networking client but it suffers the same issues connecting to later OS's as 3.11 and lacks GUI makes it even less desirable IMHO
But I'll mention it as I'm sure someone would pull me up on it if I didn't.

Windows 98 SE should be fine on that.

With regards to file sharing over the network using Windows file sharing, you can do it with modern Windows if you tweak the file sharing settings to be less secure. This should allow you to access a shared folder or drive on the 98SE PC from a modern Windows OS, in order to transfer files across.

For example on Windows 10, in Network and Sharing Center / Advanced Sharing Settings, set the following:
Current profile:
"Use user accounts and passwords to connect to other computers"
All networks:
"Enable file sharing for devices that use 40- or 56-bit encryption"

Then you need to make another change with GPEDIT (or you'll have to alter the registry manually if using a "Home" version of the OS):
In Computer Configuration / Windows Settings / Security Settings / Local Policies / Security Options:

Find the entry "Network Security: LAN Manager authentication level" and set it to "Send LM & NTLM - use NTLMv2 session security if negotiated"

Thanks so much for the help everybody!

I've installed Windows 98 SE but it does feel a bit sluggish. (I'm not sure if there is a faster option than my CompactFlash card though?)

Are there any Windows-only games that would require Windows 95 or 98 for this era? (Pentium 200/233 MMX, etc) For example, I was interested in Unreal but it seems to require a Pentium 2+ so I'll use a different machine for that.

sofakng wrote on 2021-06-24, 18:16:

Are there any Windows-only games that would require Windows 95 or 98 for this era?

If you have no interest in playing them, what difference does it make, really?

sofakng wrote on 2021-06-23, 14:30:

I'd like to use setmul.exe to play old Sierra games as well so I'm looking for something I can use for everything.

If you're already having to resort to tricks to play the games you want on this machine, why not just use ScummVM and be done with it?

My standard thing is to have two partitions on my drive: a smaller one with DOS and Windows 3.1, and a larger one with Windows 95 OSR2 or 98SE, whichever makes more sense for the particular machine.

For an MMX with 80 megs of RAM, I'd choose Windows 95. If you get OSR2, it will support FAT32.

Jorpho wrote on 2021-06-24, 18:25:

sofakng wrote on 2021-06-24, 18:16:

Are there any Windows-only games that would require Windows 95 or 98 for this era?

If you have no interest in playing them, what difference does it make, really?

I was hoping for a list of some popular games to refresh my memory so I can determine if I'm interested in any of them.

Jorpho wrote on 2021-06-24, 18:25:

sofakng wrote on 2021-06-23, 14:30:

I'd like to use setmul.exe to play old Sierra games as well so I'm looking for something I can use for everything.

If you're already having to resort to tricks to play the games you want on this machine, why not just use ScummVM and be done with it?

I'd like to use real hardware but I don't have space for several machines (ie. 386, 486, Pentium, etc)

keenmaster486 wrote on 2021-06-24, 18:45:

My standard thing is to have two partitions on my drive: a smaller one with DOS and Windows 3.1, and a larger one with Windows 95 OSR2 or 98SE, whichever makes more sense for the particular machine.

For an MMX with 80 megs of RAM, I'd choose Windows 95. If you get OSR2, it will support FAT32.

Thanks! I might go the route of using different partitions (especially because FAT16 only supports 2GB). Are you using a boot manager to select which partition to boot from or do you have to change the 'active' partition using FDISK?

sofakng wrote on 2021-06-24, 19:18:

I was hoping for a list of some popular games to refresh my memory so I can determine if I'm interested in any of them.

If you just want lists, then I suggest GOG or Mobygames.

sofakng wrote on 2021-06-23, 14:30:

I'd like to use setmul.exe to play old Sierra games as well so I'm looking for something I can use for everything.

If you're already having to resort to tricks to play the games you want on this machine, why not just use ScummVM and be done with it?

I'd like to use real hardware but I don't have space for several machines (ie. 386, 486, Pentium, etc)

Yes, but if you have to use setmul, is that really any less "real" than using ScummVM? It seems to me like it is difficult to make suggestions if this is a pursuit of subjective intangibles.

I might go the route of using different partitions (especially because FAT16 only supports 2GB). Are you using a boot manager to select which partition to boot from or do you have to change the 'active' partition using FDISK?

It doesn't really make a difference in the end. I suggest using fdisk (or gdisk) especially if you expect to be booting one partition much more frequently than the other. If you use a boot manager, you run into the small risk of something getting messed up and being unable to boot your machine until you figure out how to fix it.

sofakng wrote on 2021-06-24, 19:18:

Thanks! I might go the route of using different partitions (especially because FAT16 only supports 2GB). Are you using a boot manager to select which partition to boot from or do you have to change the 'active' partition using FDISK?

I use BOOTMGR from BTTR Software: https://www.bttr-software.de/products/bootmgr/

You shouldn't have to use FAT16 for Windows 95 if you use OSR2, and if you use the patched "7.1" version of DOS (like I do) then you can use FAT32 with your DOS partition AND install Windows 3.1 as though it were 6.22. Never had any issues with that.

Jorpho wrote on 2021-06-24, 20:45:

but if you have to use setmul, is that really any less "real" than using ScummVM?

I've seen this asked with other slowdown utilities before, and for me the answer is - it's quite different.

Turning off both caches and/or lowering the CPU multiplier can be done using just the BIOS and/or motherboard jumpers. People already did this back in the day in order to achieve compatibility with older software (not games). I have seen this with specialized bookkeeping programs that were made for 386 computers and had issues with faster CPUs. SetMul just makes these options more accessible by employing a command line program.

For the purposes of retro gaming, you also get to keep the rest of your hardware intact when using slowdown utilities. This is important if, for example, you want to use some obscure sound card with an on-board wavetable for music. Or if you fancy a proprietary 3D API like those used by Power VR and Rendition Verite cards for early 3D accelerated DOS games.

Emulation is great for people who just want basic functionality, but it's not applicable in every single use case.

Joseph_Joestar wrote on 2021-06-24, 23:35:

For the purposes of retro gaming, you also get to keep the rest of your hardware intact when using slowdown utilities. This is important if, for example, you want to use some obscure sound card with an on-board wavetable for music. Or if you fancy a proprietary 3D API like those used by Power VR and Rendition Verite cards for early 3D accelerated DOS games.

Emulation is great for people who just want basic functionality, but it's not applicable in every single use case.

Sure, but we're talking about the Sierra games! The difference between ScummVM and "original" hardware is quite indistinct, even if crazy-expensive MIDI hardware gets involved.

But whatever. How does one end up with 80 MB of RAM, anyway..?

Jorpho wrote on 2021-06-25, 01:17:

How does one end up with 80 MB of RAM, anyway..?

I'm guessing OP has 2x32 MB and 2x8 MB SIMMs installed.

Personally, I never go over 64 MB RAM on Socket 7 motherboards, as many of them can't cache anything over that amount.

As your using CF cards I'd avoid the whole dual boot thing and have 1 card for dos and 1 card for windows and swap when needed.
Again dual booting into dos 6.22 offers you nothing apart from a more complicated setup if you already have Win95 installed accept that nostalgia trip seeing the version number during bootup.
(which is a good enough reason if that's what you want)

You can get brackets that mount in a drive bay or a card slot in the back of the PC and if you get the exact same card then the PC wont even realise your swapping "hard drives" when you turn the PC on.

Game wise you can get as far as late 90's as long as the games aren't 3D heavy.
https://www.mobygames.com/browse/games/1997/windows/