I have:
A Pentium 133 for DOS/Win3.1 (Voodoo Banshee)
An Xeon 3230 for Win 98SE (Radeon 9800pro/Voodoo 2)
And a Xeon 5960 for Windows XP (GTX 780ti)

I am an overkill builder who likes to max everything out, so I think you could get by with 2 machines if you're not too picky about performance. I run Win98SE on my Pentium 133 as well for a couple of games, as well as XP on my Win 98 Machine, and Windows 10 on my XP machine just to extend their functionality further when appropriate. I also have an IBM 5170, an Amiga 2500, a Fragbox with an Athlon 3700+ with a Geforce ti4200, and a Mac PPC, but those cover other non PC and/or specific use circumstances which you could do without.

I don't think you can do Win98 on that FM2+ so you'd have to hope any 98 era game you'd like to play will be fine on XP, and without a real voodoo.

i think winXP is the start for a hyper-powerful computer like FM2. For dos, win95/98 i left first era pentium ti play with. My mainboard gas 1 PCI slot, teorically i can install a voodoo card i think. the loss of the isa slot indicates these modern computers to winxp as a minimum

P75 is a fine choice for dos gaming. Depending on your games you may run into speed issues but that's true no matter which CPU you go with.
I prefer S775 myself but FM2 with a nice fast PCIe card is great for XP

Neither does 9x era well if that matters to you?

I think it's a terrible idea only having 2 PC's 😜
but seriously if you can cover all your bases with just these 2 then its fine.

What do you want to play? And what features are important to you?

A P75 is great for mid to late DOS stuff, but is too fast (and an OEM system like an IBM isn't great for clocking back) for the really old stuff. It's also a bit slow for the very last DOS games. Sweet spot for old DOS is about 486-33 (de-turbo for XT speeds).

For XP that AM2+ thing should fine if there's driver support, although tbh I run pretty much any XP game on my daily driver Windows 10 system with Core i7.

I also miss Windows 9x in that list.

So personally I'd suggest:
- 486-33 (DX, SX, doesn't really matter) for old DOS, with 100% SB (maybe Pro) and HardMPU if you want MIDI. No TSRs as games from that era need a LOT of conventional RAM.
- fast P3 or maybe early Athlon/P4 for Win98SE and last-gen DOS games (Quake...). Nice OpenGL/D3D GPU with decent VESA DOS support (Gf4Ti, Gf FX5xxx), add a Voodoo 1 for DOS GLide, or V2 for Win9x GLide. An A3D and/or EAX sound card would be nice, but most of those don't do DOS (or interesting MIDI), so possibly use two - say an SBLive/Vortex2 and a late ISA card for DOS if possible, otherwise a nice compatible one, Yamaha YMF74x or ESS Solo-1 or similar. In Windows you can have both cards active and switch between them, in DOS simply don't initialize/load drivers for the Live/Vortex.

By all means go for an XP system too for nostalgic reasons, but It's not likely to add much n terms of compatibility between a current system and that fast P3.

Of course, if you want more systems, you can go for more fine-grained steps, but these two (plus your current system) should give you >>95% coverage.

As a target I have always had around the DX2 66 and I thought the P75 could work everything I used on the DX2 but better. For very old games I always have a 5150 available if i really want to experiment, but I don't think I go below DX2 as hardware requirements.

For games that run on windows I have recently discovered that i can use a modern platform like an FM2 and I just have an Asrock FM2A88M Extreme4 + that I have left over and which I thought (but I ask you) could cover anything that is too heavy for the P75. Maybe some games in the thousands will be too heavy for the P75 and incompatible with the FM2, but I think they are very few.

I had a P75 once, with 16mb ram (upgraded!), an 800mb hdd, a 1mb video card and something simple for sound - it was great with any DOS game, even 'late' ones like duke3d and quake, c&c and so on

to be honest for really old DOS games I tend to rely on DOSBOX for compatibility reasons

if I was to have any 2 PC's now to cover as much as possible it would be one win 98se machine of circa 2000 era specs and one windows 7 machine with circa 2015 specs, I'd accept a few incompatibilities and lots of DOSBOX usage

I'd miss XP in such a set up though!

I second dionb's comment (and he did recommend me the same some time ago 😉 ), I used to use a 486DX33 to be able to slow it down for notoriously speed-sensitive early games (pc-booter and the like) but it quickly become too limitating. I switched it for a DX2-66 and was pleasantly surprised how slow I could make it go with turbo and disabling caches, and it basically works just as good with very old games and gives me more room for later ones. For me it sits at a sweet spot and I switch to the P233MMX when the DX2-66 becomes too slow, and I have later machines for later stuff.

In your case with 2 builds you could be pretty fine depending on your goals. As you said you didn't want to go below DX2 requirements and you're not particularly interested in the very old speed sensitive stuff, the P75 should be fine.

It screams for a 3rd P3 build to sit in the middle, though. You'll eventually hear these voices in your head, I guarantee it will come, and I recommend you listen to them 😁

Considering that the fm2 motherboard has a PCI slot, inserting an old PCI video card, could the system work under windows98 too?

AlessandroB wrote on 2021-01-20, 14:18:

Considering that the fm2 motherboard has a PCI slot, inserting an old PCI video card, could the system work under windows98 too?

The bus is less relevant than if there are drivers for the card - and little things like I/O ((S)ATA), sound and network drivers. It has been done, but you can run into all kinds of headaches. If you have to ask a question like this, you're probably better off not trying...

I'm thinking about the same thing up my desk with my single 2-way KVM switch. My opinion is, that having something for XP and something else for mid-to-late DOS and Windows 9x. I don't really care about early DOS/XT and their speed sensitive software enough to keep a 486 or 386 on my desk.

My 4 candidates are:

For DOS+W9x
• PII-450 || 256MB RAM || Matrox Millennium 2 || Voodoo 2 || SB Live! SB0100
• PIII-S 1.26GHz || 512MB RAM || Geforce FX5700 || SB Audigy 2 ZS SB350
The advantage of the P2 is better compatibility with earlier DOS things, I can also add an ISA sound card something the motherboard I have for the PIII lacks the slot. The P3 however is a lot faster on late W98.

XP
• P4-3GHz || 1GB RAM || Radeon X800XT || SB X-fi SB0460
• C2D E8200 || 4GB RAM || Geforce GT240 || SB X-fi SB0460
Here it's not really a contest. The C2D seems to be the better option by far. I don't think there is major compatibility issue I know of with the more modern build, but the P4 just feels more right to me.

I think I'll go with the PIII-S and the C2D and that should decently cover about 15-ish years from the early 90s to the mid 2000s.

everyone has their own needs and their sweet spot. Mine is DX2. I have however noticed (I also had a DX2 recently) that DX2 is a little too slow for the games I want to play (Doom also doesn't work as well as I would like). In my opinion also the Pentium75 has a great charm and I consider it a valid substitute of the DX2 being more powerful but not in an exaggerated way. Having said that everything that is superior to the Pentium classic for me can be used with a computer only when it is not my sweet-spot so I prefer the compactness of a single computer to manage as much as possible.

I have several computers for playing old games and apps.

On the PC side I have:
1) 386dx-33/40 , ISA MB, with 8mb ram, 128kb cache, 2mb ET4000, SB Pro 2.0, That I can down clock to an 8088
2) 486dx4-100 with VLB MB , 16mb ram, 256kb cache, 2mb CL-5429, SB Pro 2.0, That I can down clock to 286@20mhz.
3) Pentium 233 with 128mb ram, 512mb cache, 2mb Video card, AWE64, that I can down clock to a 386dx-33 or 486dx-33
4) A few AMDK6-3+ computers running at 500mhz+, Voodoo 3000, SB live 5.1, that I can down clock to 486dx-33
5) An HP z800 with 12-core 16-threads, dual xeons, 64gb ram, GTX 960 , SB Audigy 2zs, Running WinXP

On the Mac side I have:
1) Mac SE
2) Mac color classic
3) Mac Performa 575
4) iMac G3
5) iMac G4
6) Mac G4 towers
7) Mac Pros.

So I think I am equipped to run most games and software.
To down clock just disable caches in bios and use the “Setmul” utility.