Keep both for spares.

What I would do is make an analysis of what OS / games you tend to use most? If you favor Windows gaming, keep the 550. Otherwise, keep the 450.

Personally, I tend to favor DOS gaming and multi-ISA sound card setups. So my preference is for the 450 with dual ISA cards. But that's just me, you may feel differently.

(Another option might be to keep both and upgrade the 550 into something more powerful and thus have less overlap between the systems.)

Shponglefan wrote on 2025-05-13, 18:41:

Personally, I tend to favor DOS gaming and multi-ISA sound card setups. So my preference is for the 450 with dual ISA cards. But that's just me, you may feel differently.

This is kind of where I am at because although I have machines that are far better for DOS gaming (slower Pentium class), I have an arrangement of ISA sound cards I want to play with, and having only one ISA slot really throws a wrench into the situation. My basic setup is an SB-type and the PicoGUS so I definitely would like to have both ISA slots like on the PII-450 system.

I have not tried but, it is possible I could put the PIII-550 into the BX440-based motherboard of the other one since they are both Slot-1 CPUs. But then I stray further away from the DOS dream spec.

As much as I am trying to be practical here, I'm going to end up with two computers, I can see it 😂😂

For me the spec of them is too close to justify having both. I think I would keep the PII as is, and upgrade the PIII to something a bit faster and pair with a Voodoo 3 or TNT2.

Although.... having said that... I have a fairly similar situation. I have a Pentium MMX @300Mhz and a Pentium II at 300Mhz. Sounds close, but actually the PII is quite a bit faster.

But, anyhow, To differentiate them I have the Pentium MMX paired with Voodoo 1/S3 Virge and the PII is paired with Voodoo 2 12Mb and nVidia Riva 128.

The MMX is more for DOS, but can do early Win9X games. The PII is more for Windows, but can also do DOS.

I wanted that overlap for maximum compatability during the DOS/Windows transition.

Shponglefan wrote on 2025-05-13, 18:41:

What I would do is make an analysis of what OS / games you tend to use most? If you favor Windows gaming, keep the 550. Otherwise, keep the 450.

Personally, I tend to favor DOS gaming and multi-ISA sound card setups. So my preference is for the 450 with dual ISA cards. But that's just me, you may feel differently.

(Another option might be to keep both and upgrade the 550 into something more powerful and thus have less overlap between the systems.)

All of the DOS games I know and play, which aint many however, are all speed sensitive and dont seem to like a CPU as powerful as a Pentium II.
So what DOS games are you guys talking about?

For me DOS games fall into two catagories.
Games like Hero Quest which is a DOS game in the purest form as it has no Windows installer. Then there are games like Command & Conquer Red Alert. That runs in DOS but it has a Windows installer and can run on any CPU. So really its a Windows game that runs in DOS.

ElectroSoldier wrote on 2025-05-13, 23:06:

All of the DOS games I know and play, which aint many however, are all speed sensitive and dont seem to like a CPU as powerful as a Pentium II.
So what DOS games are you guys talking about?

DOS games from about 1993 and onward. Speed sensitive games in that era tend to be the exception not the rule. First person shooter games (Doom engine, Build engine, Quake) all tend to be non-speed sensitive.

Even games like the 2nd generation Sierra games (e.g. Hero's Quest, among others) will work as they can be slowed down in-game.

edited to add:

In looking at my list of 50+ games I've tested on my Pentium 4 under DOS, over 75% work without any external speed throttling required.

Shponglefan wrote on 2025-05-13, 23:22:

DOS games from about 1993 and onward. Speed sensitive games in that era tend to be the exception not the rule.

Exactyl, these are the games I like and play, I don't really ever play anything older.
The only exception which I can never get to run, is wing Commander, that game is really picky about processor speed on anything above a 486-DX100.

kikendo wrote on 2025-05-14, 13:27:

Exactyl, these are the games I like and play, I don't really ever play anything older.
The only exception which I can never get to run, is wing Commander, that game is really picky about processor speed on anything above a 486-DX100.

Yeah, WingCommander would need a Pentium MMX with caches disabled. Unless of course you can find an appropriate 386 or 486 (cache disabled for the game).

kikendo wrote on 2025-05-13, 17:28:

I'm having a bit of a dilemma here as I landed on two systems that have a lot of overlap, namely two almost exact same Gateway […]
Show full quote

I'm having a bit of a dilemma here as I landed on two systems that have a lot of overlap, namely two almost exact same Gateway 2000 PCs, one with a PII-450 processor, and the other with a PIII-550 processor.

I've been using the PII-450 as my main old PC, running both DOS games and Windows apps, and because it has 2 ISA slots, I can use both my SB-16 Pro and my PicoGUS at the same time.
Now the 550 only has one ISA slot, and it generally seems more happy to be running Windows (actually EMM386 is failing on it for some reason, need to investigate), but otherwise the both of them are pretty much interchangeable.

What would you rather keep as an all-rounder? Would the PIII-550 be more suited to just run Windows and never MS-DOS pure mode? What would you do?
I do have a couple other older PCs more suited to DOS games, but they are laptops, so I am stuck with their configs pretty much, and I do enjoy playing around with expansion cards and whatnot.

Of course there's always the "why not both?" option, but I rather not keep both since the overlap is very big. But if I must 🤣 I will.

If you really have to choose, keep the p2-450. This cpu stands for the final pentium 2, the highest clocked and fastest available. It has cost somebody a little fortune. The p3-550 isn't top notch in its generation, thats the 600. So less speciaal.
Besides, both are basically the same cpu architecture. The only difference is SSE and that's not a big thing on this grade of CPUs.

If you really need more power you probably need a later P3, like around 1GHz or even faster. So the 450/550 isn't going to make the big difference.

waterbeesje wrote on 2025-05-14, 18:58:

If you really have to choose, keep the p2-450. This cpu stands for the final pentium 2, the highest clocked and fastest available. It has cost somebody a little fortune. The p3-550 isn't top notch in its generation, thats the 600. So less speciaal.
Besides, both are basically the same cpu architecture. The only difference is SSE and that's not a big thing on this grade of CPUs.

If you really need more power you probably need a later P3, like around 1GHz or even faster. So the 450/550 isn't going to make the big difference.

Good points! You're right about them being almost the same machine, although I do notice a difference in performance, for example, I can run Duke Nukem 3D at 800x600 on the PIII, but not on the PII.
I remember my 1Ghz PIII and I wish I had not gotten rid of it 🙁 I even had a really nice Riva TNT2 Pro card with it, with TV out.

The other difference between these setups is, that my PII-450 one is a frankenstein I built from different computer parts to approximate a Gateway 2000 model, and this new PIII system I got is just as originally built by Gateway.

I guess both CPUs are SLOT-1. Swap the 450 for 550 and you're set. Better CPU and two ISA slots.

If you want excuses to keep both.

Setup one (probably the P3) something along the lines of a fast D3D card, Creative sound card, and one of your ISA sound cards (lets say the SB16)
This is your fast D3D/EAX and also SB16 dos PC.

The other one give a 3dFX card, Vortex 2 sound card and the PicoGUS
This is your Glide, A3D, GUS PC.

Just an idea, actual hardware can obviously change depending on what you have/want.

If you really only want the 1 and you have no where else to put one of the ISA sound cards I think the decision is made for you, The P2
If you can upgrade the CPU that would make sense though.

kikendo wrote on 2025-05-13, 19:20:

This is kind of where I am at because although I have machines that are far better for DOS gaming (slower Pentium class), I have […]
Show full quote

Shponglefan wrote on 2025-05-13, 18:41:

Personally, I tend to favor DOS gaming and multi-ISA sound card setups. So my preference is for the 450 with dual ISA cards. But that's just me, you may feel differently.

This is kind of where I am at because although I have machines that are far better for DOS gaming (slower Pentium class), I have an arrangement of ISA sound cards I want to play with, and having only one ISA slot really throws a wrench into the situation. My basic setup is an SB-type and the PicoGUS so I definitely would like to have both ISA slots like on the PII-450 system.

I have not tried but, it is possible I could put the PIII-550 into the BX440-based motherboard of the other one since they are both Slot-1 CPUs. But then I stray further away from the DOS dream spec.

As much as I am trying to be practical here, I'm going to end up with two computers, I can see it 😂😂

What chipset does the one that isn't 440BX have? 440BX is one of the strongest arguments for keeping the P-II IMO

kixs wrote on 2025-05-14, 20:22:

I guess both CPUs are SLOT-1. Swap the 450 for 550 and you're set. Better CPU and two ISA slots.

From my testing the new machine these days, there are a lot of games that work way too fast on the 550. I haven't been able to test pure DOS mode yet because I ran into a sound config issue, but I wonder if this can be made better with cpuspd. The PII doesn';t have many speed stepping variables, but maybe the PIII can be controlled a bit better? Anybody knows?

chinny22 wrote on 2025-05-15, 02:14:

The other one give a 3dFX card, Vortex 2 sound card and the PicoGUS
This is your Glide, A3D, GUS PC.

I'm not rich enough to have a 3dfx card! 😂

H3nrik V! wrote on 2025-05-15, 04:45:

What chipset does the one that isn't 440BX have? 440BX is one of the strongest arguments for keeping the P-II IMO

Is there any software I can use to check this? The motherboard is unmarked for such purposes, this is an Intel-made board that they sold to Gateway. My PII's motherboard looks similar, so if I had to guess, I think this may be a 440BX2, but can't tell.
It looks very similar to these two:
https://theretroweb.com/motherboards/s/intel- … bx-warm-springs
https://theretroweb.com/motherboards/s/dell-s … 0bx-3-seattle-3

kikendo wrote on 2025-05-16, 12:59:

Is there any software I can use to check this? The motherboard is unmarked for such purposes, this is an Intel-made board that t […]
Show full quote

H3nrik V! wrote on 2025-05-15, 04:45:

What chipset does the one that isn't 440BX have? 440BX is one of the strongest arguments for keeping the P-II IMO

Is there any software I can use to check this? The motherboard is unmarked for such purposes, this is an Intel-made board that they sold to Gateway. My PII's motherboard looks similar, so if I had to guess, I think this may be a 440BX2, but can't tell.
It looks very similar to these two:
https://theretroweb.com/motherboards/s/intel- … bx-warm-springs
https://theretroweb.com/motherboards/s/dell-s … 0bx-3-seattle-3

If you run NT based operating system like NT, 2000 or XP, SIV can tell you ALL http://rh-software.com/

Cpu-Z may also present some useful data.

kikendo wrote on 2025-05-16, 12:59:

kixs wrote on 2025-05-14, 20:22:

I guess both CPUs are SLOT-1. Swap the 450 for 550 and you're set. Better CPU and two ISA slots.

From my testing the new machine these days, there are a lot of games that work way too fast on the 550. I haven't been able to test pure DOS mode yet because I ran into a sound config issue, but I wonder if this can be made better with cpuspd. The PII doesn';t have many speed stepping variables, but maybe the PIII can be controlled a bit better? Anybody knows?

What are you running that there is a speed issue with 550 and not with 450Mhz? Usually the problem software is very old from the 80s and some from early 90s. And these would run too fast even on P2-450.

If this is the case, keep a P2-450 system with two ISA slots. Newer games that would struggle on a P2-450 wouldn't run much better on a P3-550.

Just for comparison you may test both systems with both the 450 and 550, collect benchmark scores and see if it makes any sense to swap one cpu for another.

For DOS purpose you can take Phil's benchmark suite, for Windows you may look at 3D Mark 99. Also, for DOS you may look into benefits of univbe and benchmark desperately for both with and without univbe loaded.