Based on the restrictions and parts you currently have:

• Motherboard:: Gigabyte GA-6EM, because of the AGP slot.
• CPU: PII-333, being the only one with L2 cache that is officially supported with those motherboards based on the 440EX chipset. The CPU also has the multiplier unlocked downwards.
• Video card: The unnamed nVidia card is a GeForce2 GTS 32MB, pair that with the Voodoo2 card for Glide compatibility.
• Sound card: Labway A151-A00 with real OPL3 FM synth, good SBPro2 compatibility, and onboard WaveBlaster adapter.

First off you can't do what you want with this setup. No way is an early 1998 board + CPU going to be able to play 2001 games adequately. Best-case (if your slocket has an onboard voltage regulator - unlikely, and if the BIOS plays nice with an unknown CPU) you can use a Celeron 700 with slocket on one of the boards, which is a low-end 2000 CPU. More likely the P2-333 - an early 1998 part - is the best you can manage.

So you will either have to modify your requirements or choose a different platform for the high-end of your requirement.

Conversely, the Slot 1 / P2 platform is less flexible towards the low end than your old MVP4 / K6-2 build; with L1 cache disabled you can get down to 286 speeds, but not 1981 PC or 1983 XT levels (not sure what you wanted to do pre-1981 so pre IBM PC...).

That said, a P2-333 is good for all but the very last DOS games and the number of games that would be utterly unplayable on a 286-level P2 with all caches disabled is minimal. For Windows 98SE it is not a good match, it's 18 months older than Win98SE itself and though it would (with fast I/O) run the desktop perfectly well, it would be no good for demanding Win98 games.

So I would classify this as an essentially DOS-only build, in which case the Yamaha ISA sound chip (either on the card, or onboard on the MSI motherboard) is the best choice for quality (real OPL3) and compatibility (no MIDI bugs). However both motherboards have two ISA slots, so you can easily combine it with one of the AWE64 cards for SB16 and AWE synth, getting the best of both worlds.

Then VGA... absolutely no point in a Voodoo2 with this CPU, nor for higher-end GeForce stuff. Main consideration should be DOS VESA support. 3Dfx, nVidia and S3 do that excellently, ATi (onboard on the MSI) and Matrox do not. That - and not the lack of AGP port itself - is the reason I would recommend the Gigabyte board. No DOS games use Voodoo2 or later, some do use Voodoo 1, so there's something to be said for AGP 2D card plus V1, in which case the analog output quality of the 2D card is key. If the S3 Savage 4 is a from a good brand (Diamond, Number Nine etc) that would be a good choice, otherwise probably the Asus TNT2. Issue here is expansion slots - with 2x sound, 1x AGP and 1x PCI 3D, you're out of slots and can't install a network card. So unless you're a huge Tomb Raider fan, drop the Voodoo1 and use the slot for a PCI NIC. You could use the Voodoo Banshee AGP instead.

But TBH, a 'one build to do everything' based off non-optimal components in a small form factor is always going to be a compromise too far. Instead focus on one thing and do it well. This could be a good DOS box; look for a late P4 or AthlonXP build for Win98SE running 2001 games in a way that feels smooth today (we are spoiled with >>>30fps)

Thanks for the advise will take it onboard.

Currently looks like I have a bigger issue with the gigabyte board..

Unsure why it’s not detecting the PII 333 correctly.

The jumpers are setup as per the manual 5x multiplier 66.6 FSB speed. Also looks like v2.1 is the latest BIOS available for the board.

dionb wrote on 2023-10-10, 10:41:

No DOS games use Voodoo2 or later, some do use Voodoo 1, so there's something to be said for AGP 2D card plus V1

Being someone with first-hand experience with both Voodoo cards, I don't fully agree with this.

In DOS, there aren't any real compatibility loss by using the Voodoo2 card. By applying the environment variables that are in the V2-AUTO.INF file found in the Voodoo2 drivers for Windows 9x, it can run Glide games that were designed with the Voodoo Graphics card in mind. For the actually very few DOS games that still don't run with the Voodoo2 out of the box, I modded the DOS Glide 2.4x OVL libraries.

BTW, don't forget about the Windows Glide games which there are some exclusives around.

jabz11 wrote on 2023-10-10, 11:50:

Unsure why it’s not detecting the PII 333 correctly.

The jumpers are setup as per the manual 5x multiplier 66.6 FSB speed. Also looks like v2.1 is the latest BIOS available for the board.

As long as any other software detects the CPU speed correctly and there aren't any issues with microcode updates, you're good to go.

jabz11 wrote on 2023-10-10, 11:50:

Thanks for the advise will take it onboard. […]
Show full quote

Thanks for the advise will take it onboard.

Currently looks like I have a bigger issue with the gigabyte board..

IMG_0755.jpeg

Unsure why it’s not detecting the PII 333 correctly.

The jumpers are setup as per the manual 5x multiplier 66.6 FSB speed. Also looks like v2.1 is the latest BIOS available for the board.

Possibly it only supports Klamath P2 CPUs, not the newer Deschutes core of P2-333 onwards. You need a second opinion on what speed that CPU is, this could be a non-issue.

jabz11 wrote on 2023-10-10, 04:33:

AMD Athlon 64 3200+ (no suitable mainboard)

Is this a socket 754 or 939?

Gmlb256 wrote on 2023-10-10, 13:39:

[...]

BTW, don't forget about the Windows Glide games which there are some exclusives around.

I didn't, but I'd already concluded that this system would be too slow for the Win98SE requirement and as such was better viewed as a DOS-only system, and the added value of a Voodoo there is minimal unless you're a huge fan of one of the few DOS Voodoo games.

Would the same mod work for the Banshee I wonder? In that case you get the best of both worlds...

So this means the mainboard doesn’t support this CPU revision?
Damn took a bit of effort to get this far..

VivienM wrote on 2023-10-10, 22:40:

jabz11 wrote on 2023-10-10, 04:33:

AMD Athlon 64 3200+ (no suitable mainboard)

Is this a socket 754 or 939?

It’s a socket 754

dionb wrote on 2023-10-11, 05:52:

Would the same mod work for the Banshee I wonder? In that case you get the best of both worlds...

Sadly, no even if I changed the PCI device id. 🙁

Due to the MMIO address layout, the Voodoo Banshee is closer to the Voodoo3 and different than the earlier Voodoo cards (excluding Rush).

jabz11 wrote on 2023-10-11, 12:13:

VivienM wrote on 2023-10-10, 22:40:

jabz11 wrote on 2023-10-10, 04:33:

AMD Athlon 64 3200+ (no suitable mainboard)

Is this a socket 754 or 939?

It’s a socket 754

Why not find yourself a nice motherboard and build a 754 system around that CPU?

VivienM wrote on 2023-10-11, 21:48:

jabz11 wrote on 2023-10-11, 12:13:

VivienM wrote on 2023-10-10, 22:40:

Is this a socket 754 or 939?

It’s a socket 754

Why not find yourself a nice motherboard and build a 754 system around that CPU?

Feels too new to me, that's suitable for XP right? I want a dos / win98se system, I had a rethink and maybe covering 1990 - 1999

dionb wrote on 2023-10-10, 22:12:

jabz11 wrote on 2023-10-10, 11:50:

Thanks for the advise will take it onboard. […]
Show full quote

Thanks for the advise will take it onboard.

Currently looks like I have a bigger issue with the gigabyte board..

IMG_0755.jpeg

Unsure why it’s not detecting the PII 333 correctly.

The jumpers are setup as per the manual 5x multiplier 66.6 FSB speed. Also looks like v2.1 is the latest BIOS available for the board.

Possibly it only supports Klamath P2 CPUs, not the newer Deschutes core of P2-333 onwards. You need a second opinion on what speed that CPU is, this could be a non-issue.

This sounds right, the mboard is incorrectly detecting the CPU as a Klamath P2, and not the Deschutes... crap, you'd think Gigabyte would've issued a new Bios to handle these..

jabz11 wrote on 2023-10-12, 01:48:

Feels too new to me, that's suitable for XP right? I want a dos / win98se system, I had a rethink and maybe covering 1990 - 1999

It's on the ... lower end... of an XP system (okay, it's not as low end as the PIII 600/700s some of us ran XP on in 2002, but compared to a late XP-era system like an ivy bridge, or even a C2D/C2Q, the 754s are sloooooow) and on the higher end of a 98SE system?

Go and look at, say, Phil's Computer Lab on YouTube, he's done a number of 98SE builds with socket 754. Seems to think quite highly of the 754 platform with a VIA chipset for 98SE?

Ok will check out his site, how does it run the older DOS games? can it be down clocked, or hobbled to function like a 386/486 like the K2/K3 CPUs?

jabz11 wrote on 2023-10-12, 01:51:

[...]

This sounds right, the mboard is incorrectly detecting the CPU as a Klamath P2, and not the Deschutes... crap, you'd think Gigabyte would've issued a new Bios to handle these..

A Shakespeare said, that which we call a rose by any other name would smell as sweet. It doesn't matter what the BIOS tells you it thinks the CPU is, it matters whether the CPU is running at the correct speed (almost certainly is, BIOS has no influence on that om a board like this) and with things like L2 cache enabled. If it performs as a P3-333 should you're fine, whatever BIOS thinks of it.

dionb wrote on 2023-10-12, 06:05:

jabz11 wrote on 2023-10-12, 01:51:

[...]

This sounds right, the mboard is incorrectly detecting the CPU as a Klamath P2, and not the Deschutes... crap, you'd think Gigabyte would've issued a new Bios to handle these..

A Shakespeare said, that which we call a rose by any other name would smell as sweet. It doesn't matter what the BIOS tells you it thinks the CPU is, it matters whether the CPU is running at the correct speed (almost certainly is, BIOS has no influence on that om a board like this) and with things like L2 cache enabled. If it performs as a P3-333 should you're fine, whatever BIOS thinks of it.

Thanks what's the best way to determine if it's running as it should? SiSoft Sandra is detecting it as a PII 134MHz.

jabz11 wrote on 2023-10-12, 23:26:

dionb wrote on 2023-10-12, 06:05:

jabz11 wrote on 2023-10-12, 01:51:

[...]

This sounds right, the mboard is incorrectly detecting the CPU as a Klamath P2, and not the Deschutes... crap, you'd think Gigabyte would've issued a new Bios to handle these..

A Shakespeare said, that which we call a rose by any other name would smell as sweet. It doesn't matter what the BIOS tells you it thinks the CPU is, it matters whether the CPU is running at the correct speed (almost certainly is, BIOS has no influence on that om a board like this) and with things like L2 cache enabled. If it performs as a P3-333 should you're fine, whatever BIOS thinks of it.

Thanks what's the best way to determine if it's running as it should? SiSoft Sandra is detecting it as a PII 134MHz.

Try CHKCPU and SpeedSys, both are DOS programs that will display the actual CPU frequency.

jabz11 wrote on 2023-10-12, 23:26:

Thanks what's the best way to determine if it's running as it should? SiSoft Sandra is detecting it as a PII 134MHz.

I bet it is running at 133MHz, Meaning it is a semi-unlocked CPU, and it is now running at 2.0x.
Just try all the DIP switch settings in the manual and see what you get for MHz readouts.
Why would that diagnostics software (Sandra 2001) call it Klamath core? Surely that software is reading the CPUID identification directly from the CPU itself, regardless of the motherboard. And what it reads is Klamath ID 634. Deschutes would be ID 650 or 651. So maybe you misread the SL2QH code on the package, or the package was tampered with.