Could you tell a bit more about the batch files that you use? I presume it is to set the caches and maybe CPU multiplier to slow your system down?

Yes, I am setting caches and multipliers. I am also changing the FSB speed on the fly (50/66/75/83/100/112/133 MHz).

I bought this particular motherboard because it's known to work with VIA C3 flawlessly (with the PowerLeap BIOS) and it's also supported by Rayer's SMB tool.

I will post my batch files later.

As promised, some of my batch files for slowing down the VIA C3 using gerwin's excellent SetMul utility and Rayer's SMB tool.

This is roughly equivalent to Pentium 200 MMX (FSB 100 MHz, multiplier 3.5, everything enabled):

1smb /sp 10 100
2setmul 3.5 l1e l2e ice bpe

This is somewhere between 486DX-40 and 486DX2-50. I tweaked this until I got perfect speed in Ultima VII. By "perfect speed" I mean that the game is not too fast in empty areas and doesn't become too slow in busy areas. FSB 112 MHz, multiplier 6.5, L1 and L2 enabled, instruction cache and branch prediction disabled.

1smb /sp 10 112
2setmul 6.5 l1e l2e bpd icd

This is about 386DX-40 performance. FSB 50 MHz, multiplier 3.0, L1 and L2 enabled, instructions cache and branch prediction disabled.

1smb /sp 10 50
2setmul 3.0 l1e l2e icd bpd

And this is roughly equivalent to fast 286 or slow 386. FSB 50 MHz, multiplier 3.0, L1 and L2 disabled, instruction cache enabled, branch prediction disabled.

1smb /sp 10 50
2setmul 3.0 ice l1d l2d bpd

Overall I found this PC to be much better for my purposes than my previous build (AMD K6-3+) because it scales very smoothly. For example, K6-3+ with L1 disabled was just a hair too slow for Ultima VII and there was nothing I could do about it. With the C3, I can tweak the speed until I get it exactly as I want it.

> I probably need to get a modular PSU to get rid of that nasty bundle of wires, but at least I managed to mostly clear up the area around the PSU and RAM.

Can confirm a modular picoATX psu works well (I use 120w), it's not just about clearing away the wires - you also get room for full length ISA cards which is the main reason I did it, I have a nice AWE32 sitting in my Lian Li HTPC case with a similar layout to yours.

ShovelKnight wrote on 2020-05-25, 16:16:

This is my VIA C3-based retro PC. […]
Show full quote

This is my VIA C3-based retro PC.

I went with this CPU because I wanted to get maximum flexibility in running games from different eras. I'm running it at 133 MHz FSB and the system is very stable. Initially I went with GeForce 2MX AGP but I had some occasional freezes due to 89 MHz AGP clock, so I swapped it out in favour of Elsa Gladiac 511.

The floppy drive is not really necessary, but I missed the floppy boot seek sound and decided to add a floppy drive to this PC for nostalgia's sake 😀

Components:
- VIA C3 Ezra 800 MHz CPU (I usually run it at 866 MHz)
- MSI MS-6905 Master V2 slotket
- Gigabyte GA-6BXC Rev. 2.0 motherboard
- 384 MB of PC133 SDRAM
- 32GB CF card on an adapter
- Elsa Gladiac 511 (GeForce 2MX PCI)
- ESS 1869F ISA sound card
- GoTek floppy emulator with Flash Floppy firmware
- Alps 3.5" floppy drive
- Cooler Master Elite 360 case
- FSP 400W OEM PSU

Photos:

Sorry for not showing the system in its rightful place, but since I'm working from home, I have some confidential crap on my desk. The case is one of the smallest full ATX cases ever made, that's why it's very cramped inside and cable management is a major pain. I probably need to get a modular PSU to get rid of that nasty bundle of wires, but at least I managed to mostly clear up the area around the PSU and RAM.

The system runs games from 1985 to late 1990s without major issues. I'd also like to get a VIA Nehemiah CPU which should be fast enough to run most games released up to 2001 or so, even though it's not as flexible in terms of CPU scaling. At the moment I have several .BAT-files that allow me to easily go from full speed (roughly equal to PII-450) to slow 386/slow 486/fast 486/slow Pentium levels of performance.

Your Slotket has jumper selection for VIA cpus or just Cyrix?
My slotket has only jumper for celeron, Coppermine and Cyrix only
No sure if my C3 (Erza 866) will run on Asus p3b-f 1.04

MKT_Gundam wrote on 2020-05-27, 22:06:

Your Slotket has jumper selection for VIA cpus or just Cyrix?
My slotket has only jumper for celeron, Coppermine and Cyrix only
No sure if my C3 (Erza 866) will run on Asus p3b-f 1.04

This slotket (MS-6905 Master) doesn't explicitly support VIA C3 or "Cyrix" CPUs. It has the following jumpers:

- 2 "reserved" (function unknown)
- 2 FSB clock selection jumpers
- 5 voltage selection jumpers
- 1 CPU selection jumper: single/dual/Coppermine 256

ShovelKnight wrote on 2020-05-27, 22:14:

This slotket (MS-6905 Master) doesn't explicitly support VIA C3 or "Cyrix" CPUs. It has the following jumpers: […]
Show full quote

MKT_Gundam wrote on 2020-05-27, 22:06:

Your Slotket has jumper selection for VIA cpus or just Cyrix?
My slotket has only jumper for celeron, Coppermine and Cyrix only
No sure if my C3 (Erza 866) will run on Asus p3b-f 1.04

This slotket (MS-6905 Master) doesn't explicitly support VIA C3 or "Cyrix" CPUs. It has the following jumpers:

- 2 "reserved" (function unknown)
- 2 FSB clock selection jumpers
- 5 voltage selection jumpers
- 1 CPU selection jumper: single/dual/Coppermine 256

My actual VIA c3 rig uses S370 ASUS CUV4X with just 1 ISA slot. I really wanted more ISA slots.

Does your slotket has a voltage clamp? If yes, then you could just try it with your VIA C3 in the ASUS motherboard.

ShovelKnight wrote on 2020-05-27, 23:08:

Does your slotket has a voltage clamp? If yes, then you could just try it with your VIA C3 in the ASUS motherboard.

Heres the slotket

Hmm, no voltage clamp as far as I can see, but should still be OK if the motherboard conforms to Intel VRM 8.4 spec.

Ah the fantastic GA-6BXC Rev. 2.0 - I've bought backups! I'm using the same exact board and slotket with my Ezra. Although I have an 866hz, a 1.2 (or was it 1.4?) ghz Nemehiah, and a 1.0Ghz Ezra-T (which has the most multiplier options out of all of them). The Nehemiah actually can go slower than the Ezras and obviously faster-- but it just fails at the mid ranges... like 486DX2. I bought several slotket cards so I can keep them all ready to swap -- I even have a PIII Tualatin (1.4) on one BUT the board or slotket (or both) will not run it at 133FSB no matter what. So I have to downclock it to 100FSB.

All VIA CPUs do 133FSB just fine, though.

infiniteclouds wrote on 2020-05-29, 03:59:

Ah the fantastic GA-6BXC Rev. 2.0 - I've bought backups! I'm using the same exact board and slotket with my Ezra. Although I have an 866hz, a 1.2 (or was it 1.4?) ghz Nemehiah, and a 1.0Ghz Ezra-T (which has the most multiplier options out of all of them). The Nehemiah actually can go slower than the Ezras and obviously faster-- but it just fails at the mid ranges... like 486DX2. I bought several slotket cards so I can keep them all ready to swap -- I even have a PIII Tualatin (1.4) on one BUT the board or slotket (or both) will not run it at 133FSB no matter what. So I have to downclock it to 100FSB.

All VIA CPUs do 133FSB just fine, though.

Actually, I bought this motherboard after reading your and Gerwin's posts about it. It's really good. I'm keep my eyes open for another one.

I wish I could find an Ezra-T, they are extremely rare! I suspect it would overclock better than my current Ezra that only does 866 MHz. My VIA Epia 800 would do 1 GHz easily but the board itself is very quirky and no ISA slots is a deal breaker.

Some changes to the PC.

I replaced the sound card with this nice AOpen AW37. I like the sound of CrystalFM, and this sound card has a much cleaner output than my no-name ES1869F.

I also made a small adapter to connect the PC speaker output of the motherboard to the mono input of the sound card. I almost feel dirty for using this nice Wima capacitor here, but it was the only non-polar capacitor I had in stock (well, I do have some Soviet NOS military spec film and paper in oil capacitors... but they would be totally inappropriate here).

Well, it all works and now I can play Ultima V and listen to the glorious PC speaker sounds through my planar headphones 😀

Glad the build worked out so well for you. Hey, is Ultima V the last... or rather, at least... the most 'demanding' game that still uses PC speaker?

Cool build! I just finished a build based around the PC Chips M789CG v3.0 which has a VIA Samuel C3 800 onboard. It had a lot of bad caps that needed to go, even though it still ran with them, but it wasn't detecting IDE/Floppy at each boot before the recap.

The idea with routing PC speaker to the mono sound card input is awesome. Is the GeForce's clock an issue with the VIA CPU itself?

Mine's running on a Quantum Fireball for a hard drive since I couldn't find where I left my spare SD to IDE adapter. That drive is noisy!

Also, you should do the Flashfloppy speaker mod so that you can have the drive sounds.

infiniteclouds wrote on 2020-06-01, 06:10:

Hey, is Ultima V the last... or rather, at least... the most 'demanding' game that still uses PC speaker?

I guess so! It's interesting that the Atari ST version had a MIDI soundtrack but it was never implemented in the PC version.

The game is still totally awesome even with PC speaker sounds.

pii_legacy wrote on 2020-06-01, 06:55:

Is the GeForce's clock an issue with the VIA CPU itself?

The i440BX chipset was never rated for 133 MHz FSB, it has only two setting for AGP clock: 1 (same as FSB clock) and 2/3. With FSB at 133 MHz, AGP is running at 89 MHz which is higher than the spec (66 MHz). Not all AGP GPUs operate correctly at this frequency, I guess my GeGorce 2MX is one of them.

Surprisingly, i440BX does have 1/4 divider for PCI clock so PCI bus stays in spec even at 133 MHz FSB.

ShovelKnight wrote on 2020-06-01, 08:40:

infiniteclouds wrote on 2020-06-01, 06:10:

Hey, is Ultima V the last... or rather, at least... the most 'demanding' game that still uses PC speaker?

I guess so! It's interesting that the Atari ST version had a MIDI soundtrack but it was never implemented in the PC version.

The game is still totally awesome even with PC speaker sounds.

My mistake -- I was thinking of Ultima VI which apparently even though it can use up to an MT-32 for music still uses PC Speaker for sound effects.

ShovelKnight wrote on 2020-06-01, 08:46:

pii_legacy wrote on 2020-06-01, 06:55:

Is the GeForce's clock an issue with the VIA CPU itself?

The i440BX chipset was never rated for 133 MHz FSB, it has only two setting for AGP clock: 1 (same as FSB clock) and 2/3. With FSB at 133 MHz, AGP is running at 89 MHz which is higher than the spec (66 MHz). Not all AGP GPUs operate correctly at this frequency, I guess my GeGorce 2MX is one of them.

Surprisingly, i440BX does have 1/4 divider for PCI clock so PCI bus stays in spec even at 133 MHz FSB.

Thanks for the info! The C3 really is underrated, I am loving mine.