Finding the magic CPU for vintage 386 DOS to Pentium III performance

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Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby tpowell.ca » 2019-2-11 @ 15:47

So, after building multiple systems to try and get performance that can be crippled down to low 386 levels required by older DOS games, but at the same time, being powerful enough to play some of the early Windows 98 Direct3D games, I started building a chart (WORK IN PROGRESS).
CPU vintage testing.png

We all know that the AMD K6+ series CPUs are excellent at reaching a very wide performance range, and doing so in hardware, but their Windows performance is, in my opinion lackluster, and extremely picky with respect to memory, AGP videocards and drivers. Obviously, a Pentium III does give you fantastic Windows 98 performance but completely useless for vintage DOS gaming.
That's where the VIA C3 comes in.
My test for minimum required Windows 98 performance is the CPUs ability to decode in real-time MPEG2 video such as that in the Wing Commander IV DVD version without the use of dedicated hardware decoding.
The VIA C3 Ezra-T and the Nehemiah were both able to playback MPEG2 video, have unlocked multipliers, under/overclock VERY well, and produce very little heat.
Couple that with an Intel BX chipset and you get a far more reliable experience than you would on an ALI or VIA chipset for a super socket 7.

What I've build around the VIA C3 CPU:
-Antec NSK 4400 ATX case
-Seasonic ATX power supply
-Micron 512 MB PC133 CL2 RAM
-Gigabyte GA-6BXC Rev 2.0 motherboard (with PowerLeap BIOS)
-MSI MS-6905 Master slotket Rev 2.0
-Via C3 Ezra-T 1000 (100MHz x10) running at 1223MHz (112MHz x11)
-nVidia Quadro FX500 128MB AGP
-Powercolor Voodoo2 12MB PCI
-Corsair F120 120MB SATA SSD
-Promise SATA150TX2 PCI controller
-intel Gigabit PCI NIC
-TSSTcorp TS-H492C IDE DVD-ROM (with digital out connected to Yamaha soundcard)
-Yamaha YMF744 XG/OPL3 PCI soundcard using SB-Link
-Gravis Ultrasound PnP 16MB

So far, nothing I've tried on this setup failed that didn't also fail on my AMD K6-III+ setup with the DFI motherboard.
And unlike the K6-III+, I've had ZERO bleuscreens or freezes.

NOTES:
[1] 3.0x to 16.0x, 27 choices
[2] 4.0x to 16.0x, 25 choices
[3] 2.0x to 6.0x in 0.5x increments, 8 choices (2.5x is excluded).
[4] L2 runs at half-CPU core speed. 333 / 2 = 166MHz
[5] L2 runs at half-CPU core speed. 500 / 2 = 250MHz
[6] Gigabyte GA-6BXC
* MSI-6905 Master v2 slotkit adapter^
* Micron 512MB CL2 PC133 SDRAM (3 sticks)
* nVidia Quadro FX500 128MB AGP (driver version 56.64)
* FastVid loaded for DOS Benchmarks
^ for Socket 370 CPUs only.
[7] DFI K6XV3+/66
* nVidia Quadro FX500 128MB AGP
* FastVid loaded for DOS Benchmarks
[8] OVERclocked, 1224MHz (112MHz x11.0)
[9] OVERclocked, 1224MHz (112MHz x11.0)
[10] OVERclocked, 500MHz (100MHz x5.0)
[11] UNDERclocked, 612MHz (112MHz x5.5)
[12] UNDERclocked, 780MHz (112MHz x7)
[13] OVERclocked, 500MHz (100MHz x5.0)
[14] PhilsComputerLab benchmark, Max Detail mode
[15] DOS 320x200, No Sound
[16] 640x480, No Sound
[17] nVidia Quadro FX500 128MB AGP
[18] 3dfx Voodoo2 12MB PCI
[19] High Quality (800x600), No Sound
Last edited by tpowell.ca on 2019-2-12 @ 00:53, edited 4 times in total.
    Merlin: MS-4144, AMD5x86-160, 32MB, 16GB CF, ZIP100, ESS688, GUS, S3 VirgeGX 2MB, HardMPU
    Newton: K6XV3+/66, AMD K6-III+500, 256MB, 32GB SSD, AWE32, GUS 16MB, Voodoo3-3k
    Einstein: P8P400, P4-3GHz HT, 1.5GB, Quadro4 980XGL, Live!
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby tpowell.ca » 2019-2-11 @ 15:49

Some of you may note the rather low FPS numbers in the DOS benchmarks. This is due to the nVidia Quadro FX500 card.
    Merlin: MS-4144, AMD5x86-160, 32MB, 16GB CF, ZIP100, ESS688, GUS, S3 VirgeGX 2MB, HardMPU
    Newton: K6XV3+/66, AMD K6-III+500, 256MB, 32GB SSD, AWE32, GUS 16MB, Voodoo3-3k
    Einstein: P8P400, P4-3GHz HT, 1.5GB, Quadro4 980XGL, Live!
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby Baoran » 2019-2-11 @ 17:08

Is there any solution to performance not being stable when slowing down such fast cpus to 386 levels? Like for example when I did original wing commander with K6-III+ with caches disable it was correct speed some of the time but it also seemed to randomly speed up to too fast speeds. I have had much more stable performance when I have slowed down 486 33Mhz to correct speed for wing commander.
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby Intel486dx33 » 2019-2-11 @ 17:47

This guy recommended this motherboard but I don’t know if it would work.
viewtopic.php?f=25&t=62057&start=20#p695935

And this one
viewtopic.php?f=25&t=62057&start=20#p696461
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby tpowell.ca » 2019-2-11 @ 18:57

One advantage that I know of with the GA-6BXC over other potential boards is its compatibility with Rayers FSB utility where you can select the following FSBs without rebooting:
50, 66, 75, 83, 100, 103, 112, 133MHz

Couple that with setmul, giving you 25+ multiplier settings to play with, plus L1, L2, Branch Prediction and Instruction Cache all individually controllable.
Last edited by tpowell.ca on 2019-2-12 @ 16:44, edited 1 time in total.
    Merlin: MS-4144, AMD5x86-160, 32MB, 16GB CF, ZIP100, ESS688, GUS, S3 VirgeGX 2MB, HardMPU
    Newton: K6XV3+/66, AMD K6-III+500, 256MB, 32GB SSD, AWE32, GUS 16MB, Voodoo3-3k
    Einstein: P8P400, P4-3GHz HT, 1.5GB, Quadro4 980XGL, Live!
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby Tenorman » 2019-2-12 @ 01:08

Interesting. Thanks for posting your results.

It's funny that I am beating you at 3D Mark 99 even though my CPU is running 200 Mhz slower with a much worse video card. My guess would be that Nvidia's hardware and drivers get progressively less DX 6 optimized the newer you get.

Your Quake 3 scores somewhat of are an eye-opener. Your CPU is 20% faster and don't have sound enabled, but your score is ~170% of mine. I had intentionally not bothered to put much of a video card in my system because I figured the CPU would be too much of a bottleneck, but it looks like I need to give this thing a bit more credit.

---
C3 Ezra 866@1.0 Ghz (112x9)
Unreal Tournament (800x600x16, high detail): S3 Savage4 Pro (Metal) - 53 FPS, TNT2 M64 @ 143 Mhz - 32 FPS, TNT2 M64 @ 180 Mhz - 38 FPS
Quake 3 Demo 001 (800x600x16, high quality, OpenGL): S3 Savage4 Pro - 31.5 FPS, TNT2 M64 @ 143 Mhz - 35.4 FPS, TNT2 M64 @ 180 Mhz - 40 FPS
3D Mark 2000 (default settings): S3 Savage4 Pro - 993, TNT2 M64 @ 143 Mhz - 1698, TNT2 M64 @ 180 Mhz - 1880
3D Mark 99 (default settings): S3 Savage4 Pro - crash, TNT2 M64 @ 143 Mhz - 4038, TNT2 M64 @ 180 Mhz - 4162
[Compaq Presario 633 | DOS 6.22 / Win 3.1 | DX4 100 Overdrive | 28M RAM | SB16 CT2770A | SPEA Media FX (Soundscape S2000) ]
[GA-6BXC R2.0 | Win98SE | Via C3 Ezra 866 | 384M RAM | TNT2 32M | Voodoo2 8M | SB32 CT3670 | Ensoniq Soundscape Opus]
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby tpowell.ca » 2019-2-12 @ 13:33

I believe drivers make a huge difference. I'll be trying some older drivers, see if I gain anything and resolves my issues with 3DMark on VIA CPUs.
I also want to see how much a different videocard makes of a difference in DOS. I'm debating between a Voodoo3 and a TNT2 for those tests.
    Merlin: MS-4144, AMD5x86-160, 32MB, 16GB CF, ZIP100, ESS688, GUS, S3 VirgeGX 2MB, HardMPU
    Newton: K6XV3+/66, AMD K6-III+500, 256MB, 32GB SSD, AWE32, GUS 16MB, Voodoo3-3k
    Einstein: P8P400, P4-3GHz HT, 1.5GB, Quadro4 980XGL, Live!
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby gerwin » 2019-2-12 @ 18:50

tpowell.ca wrote:I also want to see how much a different videocard makes of a difference in DOS. I'm debating between a Voodoo3 and a TNT2 for those tests.

Hardly any difference between good VESA videocards, like TNT/Geforce up to around the FX series and the Voodoo 3. What makes a big difference is FSB speed in combination with Write Combining CPU support (Rayer's MTRRLFBE tool). The high res DOS games use VESA LFB modes, which are all about transferring the framebuffer over the bus as fast as possible.

About your Pentium II Deschutes 333MHz. You got unlucky there. If the datecode was like 9830, instead of 9902, you would have had an unlocked one.
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby tpowell.ca » 2019-2-12 @ 20:50

gerwin wrote:
tpowell.ca wrote:I also want to see how much a different videocard makes of a difference in DOS. I'm debating between a Voodoo3 and a TNT2 for those tests.

Hardly any difference between good VESA videocards like TNT/Geforce up to around the FX series and the Voodoo 3. What makes a big difference is FSB speed in combination with Write Combining CPU support (Rayer's MTRRLFBE tool). The high res DOS games use VESA LFB modes which are all about transferring the framebuffer over the bus as fast as possible.

About your Pentium II Deschutes 333MHz. You got unlucky there. If the datacode was like 9830 instead of 9902 you would have had an unlocked one.


Interesting. I'll have to try the MTRRLFE tool.
As for the PII, its not a huge issue. I really don't plan on using it for anything. I'm actually impressed by its ability to overclock from 66MHz to over 112MHz FSB and be rock stable.
    Merlin: MS-4144, AMD5x86-160, 32MB, 16GB CF, ZIP100, ESS688, GUS, S3 VirgeGX 2MB, HardMPU
    Newton: K6XV3+/66, AMD K6-III+500, 256MB, 32GB SSD, AWE32, GUS 16MB, Voodoo3-3k
    Einstein: P8P400, P4-3GHz HT, 1.5GB, Quadro4 980XGL, Live!
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby doaks80 » 2019-2-12 @ 21:03

I use a K6-3+ with plain DOS6 and my only complaint is it doesn't go slow enough. I can't get it lower than about a 386DX33. On my first Win98 machine I have a C3 866mhz, which struggles with games from the late 90s (probably anything past Quake2), yet when I turn off all caches using setmul it cripples win98 so badly to be unusable, it might be a 286. I don't currently run win98 on my K6-3+, but iirc from the 90s I had a non-mobile K6-266 and it ran win95 and then win98 just fine.
k6-3+ 400 / s3 virge DX+voodoo1 / awe32(32mb)
via c3 866 / s3 savage4+voodoo2 sli / audigy1+awe64(8mb)
athlon xp 3200+ / voodoo5 5500 / diamond mx300
pentium4 3400 / geforce fx5950U / audigy2 ZS
core2duo E8500 / radeon HD5850 / x-fi titanium
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby gerwin » 2019-2-12 @ 21:20

gerwin wrote:which are all about transferring the framebuffer over the bus as fast as possible.

If all is well this VESA framebuffer is video memory. So I should have written: transferring pixels to the framebuffer over the system bus.
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby j^aws » 2019-2-12 @ 22:10

Baoran wrote:Is there any solution to performance not being stable when slowing down such fast cpus to 386 levels? Like for example when I did original wing commander with K6-III+ with caches disable it was correct speed some of the time but it also seemed to randomly speed up to too fast speeds. I have had much more stable performance when I have slowed down 486 33Mhz to correct speed for wing commander.

The solution is to be able to control CPU limitations as well as VGA/ graphics limitations:
viewtopic.php?p=578020#p578020

You can see how a Tseng ET4000AX ISA card limits CPU scaling, with forced 8bit and 16bit bus restrictions affecting both top and bottom benchmark performance. Most speed sensitive builds focus on CPU scaling, leaving a relatively fast VGA/ graphics system which can create spikes in performance.

When you mention slowing down a real 486 CPU, you have a VGA/ graphics system more in line with your 486 - not some modern, ultra fast graphics system which can create spikes in performance.

A flexible build is one that can be both CPU and VGA/ graphics limited, whereby tuning these subsystems creates an appropriate period balance.
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby LunarG » 2019-2-13 @ 10:19

I wonder why so many people have nothing but negative things to say about K6(II-3) and Via chipsets. I can't help wondering if people just don't install the 4-in-1 drivers or something. Perhaps the only Via super 7 board I've used, AOpen AX59Pro, simply is THAT good(?), but I've never really had any major issues unless I've ignored the chipset drivers. But then again, even Intel chipset boards also don't work wonderfully without drivers installed, the only big difference is that pretty much all versions of Windows come with rudimentary Intel drivers bundled.

The C3 sounds like an interesting option. Never tried one myself. Then again, I'm not really into the whole slow-down method. I instead seem to prefer having to use lots of space, and mess around with more or less working KVM options *sigh* Each method has its merits for sure. :D
WinXP : PIII 1.4GHz, 512MB RAM, 73GB SCSI HDD, Matrox Parhelia, SB Audigy 2.
Win98se : K6-3+ 500MHz, 256MB RAM, 80GB HDD, Matrox Millennium G400 MAX, Voodoo 2, Waveforce 192XG.
DOS6.22 : Intel DX4, 64MB RAM, 1.6GB HDD, ELSA Winner 1000PRO, GUS 1MB, SB16.
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby Tenorman » 2019-2-13 @ 14:39

Related to the comments about needing slower video options and preferring KVMs / multiple machines:

What I found with my build is that you will end up with something pretty versatile that you will use a lot, but a C3 time machine won't replace all your other computers. The performance characteristics are kind of weird because pretty much everything except the CPU is still much faster than expected. For example, if I slow down my machine all the way (50 x 3, L1D, L2D, BPD, ICD) I should basically have a very slow 386. I still find however that sound does not work on Ultima 6 without the Adlib Patch. My 486 DX4 100 will play this game just fine, no patching, by just disabling the L1 cache because the rest of the machine is more in line with what the game is expecting. More generally, you can adjust the FSB and multiplier to give numbers very similar to a specific CPU in Speedsys, but when you run a game such as Doom the performance will be nothing like what you'd expect. The best approach is not to think about it too much and just find settings that work for whatever you are trying to do.
[Compaq Presario 633 | DOS 6.22 / Win 3.1 | DX4 100 Overdrive | 28M RAM | SB16 CT2770A | SPEA Media FX (Soundscape S2000) ]
[GA-6BXC R2.0 | Win98SE | Via C3 Ezra 866 | 384M RAM | TNT2 32M | Voodoo2 8M | SB32 CT3670 | Ensoniq Soundscape Opus]
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Re: Finding the magic CPU for vintage 386 DOS to Pentium III performance

Postby LunarG » 2019-2-13 @ 16:00

Tenorman wrote:Related to the comments about needing slower video options and preferring KVMs / multiple machines:

What I found with my build is that you will end up with something pretty versatile that you will use a lot, but a C3 time machine won't replace all your other computers. The performance characteristics are kind of weird because pretty much everything except the CPU is still much faster than expected. For example, if I slow down my machine all the way (50 x 3, L1D, L2D, BPD, ICD) I should basically have a very slow 386. I still find however that sound does not work on Ultima 6 without the Adlib Patch. My 486 DX4 100 will play this game just fine, no patching, by just disabling the L1 cache because the rest of the machine is more in line with what the game is expecting. More generally, you can adjust the FSB and multiplier to give numbers very similar to a specific CPU in Speedsys, but when you run a game such as Doom the performance will be nothing like what you'd expect. The best approach is not to think about it too much and just find settings that work for whatever you are trying to do.


Yes, I have sort of gotten the impression that there's very little "press power and play" involved with time machine builds, which is one of the reasons I've not gone with that route. Currently, I own 4 completed retro systems, but I suspect I'll be putting some spare parts to use to build a 5th one. Hooking it all up to monitors, speakers, input devices etc. can be an issue though. I have limited space, and I really need to come up with some creative solutions to make it all usable without unplugging/replugging and other fiddly stuff.
I totally see the appeal of an all-in-one solution, but I also do really like the old hardware. There's just something more authentic and nostalgic about playing games on actual old hardware. I just wish I had more space for all this stuff. And just imagine how bad it will get if I start dragging an old Amiga into the flat as well *shrug* Oh well. :D
WinXP : PIII 1.4GHz, 512MB RAM, 73GB SCSI HDD, Matrox Parhelia, SB Audigy 2.
Win98se : K6-3+ 500MHz, 256MB RAM, 80GB HDD, Matrox Millennium G400 MAX, Voodoo 2, Waveforce 192XG.
DOS6.22 : Intel DX4, 64MB RAM, 1.6GB HDD, ELSA Winner 1000PRO, GUS 1MB, SB16.
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