First post, by Joseph_Joestar
- Rank
- l33t++
System specs
- Intel Pentium MMX 200 MHz
- QDI P5I430TX Titanium IB+ (Intel 430TX)
- 64 MB SDRAM
- Matrox Millennium II 4 MB
- ESS AudioDrive 1868F
- Sound Blaster 16 MCD (CT1750)
- Samsung 3.5" floppy drive
- CF to IDE adapter + Transcend 2 GB Industrial CF card (CF300)
- Philips 40x CD-ROM
- LC Power 550W PSU
- LG Flatron L1753HR 17" LCD monitor
- Cambridge SoundWorks Digital 2.1 Speakers
Introduction
Another DOS focused Pentium MMX build, but with a slight twist. Thanks to the QDI Titanium motherboard, this rig has a lot more slowdown options. More details below.
CPU
This Pentium MMX 200 CPU has enough power to comfortably run most DOS games. It does struggle with late 3D SVGA titles like Quake and Tomb Raider when using software rendering, but I have a different, much more powerful system which can properly handle such games. The best thing about this CPU is that it can be slowed down to 386 and 486 levels which is important for a number of speed sensitive games. By using SetMul and optionally disabling the motherboard L2 cache in the BIOS, it's possible to fine tune CPU speed.
For example, with both L1 and L2 caches disabled, along with SetMul BPD VPD, the system runs like a slow 386, which is nice for the original Wing Commander. On the other hand, with just SetMul CCD applied, while leaving both caches enabled, the system behaves like a fast 486. That's great for games like One Must Fall 2097 and WarCraft 1 which run too fast on a Pentium but too slow on a 386. There are other in-between speeds that can be reached using the Pentium test registers as showcased in this video by Phil. Finally, since this CPU tops out at 200 MHz, it isn't affected by the dreaded "Runtime Error 200" issue which plagues many DOS games from this time period (e.g. Jazz Jackrabbit). I know that there are patches and workarounds for that, but it just feels nice not having to worry about it at all.
For DOS games which crash due to too much RAM, I use XMSDSK & EMSDSK which lowers the available memory to 32 MB and that usually solves the issue. If necessary, it's possible to lower the memory even further (e.g. to 8 MB) in case some game needs that. And for games that don't like fast CD-ROM devices, I use the excellent CDBeQuiet! utility which sets the drive speed to 4x, making it blissfully quiet in the process.
Motherboard
The QDI Titanium IB+ motherboard is based on the Intel 430TX chipset, but it has some unique features. Most importantly, it allows you to change the CPU frequency directly from the BIOS, without setting any jumpers. This is very useful if you need to slow down the CPU even further. As an example, I can easily set my Pentium MMX 200 to run at 100 MHz (2x50) straight from the BIOS. The board also has a PS2 mouse header, with its pinout properly documented in the manual, which is helpful in case you need to rewire a generic bracket to fit there. My only nitpick with this motherboard is that the Power LED gets dimmed instead of turned off when using an ATX power supply. Fortunately, this can be worked around by connecting the Power LED to the Sleep LED header, as described here.
Graphics card
The Matrox Millennium II is another highlight of this build. Image quality is exceptional for its time (250 MHz RAMDAC) and the WRAM is an interesting feature as well. Additionally, it can use the proprietary MSI (Matrox Simple Interface) API which some DOS games like Tomb Raider do support. Its DOS compatibility isn't perfect, but some of the issues can be worked around. For example, the choppy scrolling in Jazz Jackrabbit can be eliminated by slowing down the CPU to 100 MHz, as mentioned earlier. And a similar issue in Commander Keen 4 can be resolved by enabling the in-game "Fix Jerky Motion" setting. Anyhow, I think the exceptional image quality that this card brings to the table outweighs these minor compatibility issues.
Sound card #1 - ESS AudioDrive 1868F
I like the SBPro style low-pass filter on this card, as it makes digital audio softer and more pleasant in some older DOS titles. It also has a native AudioDrive mode which can bring 16-bit audio to supported games, but that has some issues which can be partially worked around. The ES1868F also supports ADPCM so Duke Nukem 2 sounds as it should. Best of all, its output is pretty much noise-free, when the jumper is set to the Line Out position. The FM synthesis on this card (ESFM) sounds excellent and gets very close to genuine OPL3. I'd even say that ESFM sounds a bit less "buzzy" and more melodic than true OPL3 which, while different, can produce a more pleasing result on some tracks. Here are some samples:
The enhanced ESFM functionality is also interesting in games which support that. Lastly, the MPU-401 interface on this card is completely bugfree, which makes it a great choice for connecting an external MIDI device. In this build, I have the card configured for A220 I7 D1 P330 T4 which provides excellent compatibility for older DOS games, i.e. its primary use case.
Sound card #2 - Sound Blaster 16 MCD CT1750
This is one of the earlier SB16 models, and it doesn't support Plug and Play, so everything needs to be configured via jumpers. I first moved the OPSL and OPSR jumpers to disable the on-board amp, as per Cloudschatze's instructions here. Doing that and using the optimized the mixer settings from that post pretty much eliminates all self-noise on this classic SB16.
Unfortunately, my particular card uses DSP v4.12, so it has all the relevant hanging note bugs. That's not an issue though, since the ESS 1868F will handle all MPU-401 duties. This SB16 also suffers from DMA clicking in older games, but once again, the ESS AudioDrive will come to the rescue in such cases. This card is also very long, so I could only fit it into the third ISA slot on this motherboard, and just barely. Where the CT1750 will shine are late-era DOS games which benefit from 16-bit audio. Examples include Crusader: No Remorse/No Regret, Privateer 2 and Heroes of Might and Magic 2. The SB16 has been configured to use A240 I5 D3 H7 P300 T6, which isn't a problem for later DOS games, as they often allow you to select these parameters manually in setup. Lastly, this card has a genuine Yamaha YMF262-M chip on board, for that authentic OPL3 sound.
Operating System
On this machine, I currently use a single 2 GB CF card with MS-DOS 6.22. No Windows here, as this build is purely focused on DOS gaming. With all the drivers loaded, I have 610 KB of conventional memory free, which is enough for 99% of the games that I play.
Conclusion
The versatility of this system is really something. The SpeedEasy BIOS settings make it extremely simple to change the CPU speed, giving even more slowdown options when paired with SetMul. In terms of upgrades, I plan on getting a front loading StarTech CF to IDE adapter and putting the system in a better case. The one I'm using right now is old and dingy, but it's what I currently had on hand.
