Memory: 32MB FPM*. Your board uses the Intel 420ZX Saturn II chipset so you need 2x16MB or 4x8MB 72pin FPM because of memory interleaving.
Video: S3 Trio64V+ 2MB.
Sound: AWE64 if you do not care about having a real OPL3 chip (if you do it complicates things¤).
Sound: Your Roland modules connected to the AWE64, use SoftMPU when needed.
CPU: Your DX4 100 is fine, there is no official support for anything faster except for the Pentium Overdrive.
Nettwork card: 3com EtherLink III 3C509B.

*If you upgrade to or already have 512KB cache memory you can use 2x32MB or 4x16MB FPM, this is not really needed though.
*The memory compatibility is probably shoddy so expect to try more than one set of memory before you find memory that works ok.
¤ Then you need an AWE32 CT2760/CT3900/CT3980 and also a Roland MPU-401 or some other non bugged MPU-401 to connect your Roland modules.

If you happen to find a Roland SCC-1 that wont cost you an arm and a leg get it but it will only do the exact same thing as your SC-55 and you probably need to build a cable your self if you want to use it's MPU-401 to connect your CM-64 or MT-32.

Thanks Skyscraper!

I currently have a quantum ligtning 730s scsi harddrive installed and I am not sure if I should (or even can) install one of the scsi2sd adapters to remove the noise out of my tower. is there a big speed increase while using a scsi instead of an ide in a 486? does it even make sense for dos gaming?

what do you think about this board any way? is it worth keeping or should I move on to a newer UMC8111F chipset.

The Asus PCI/I-486SP3G MB should be decent, better than most Socket-3 motherboards even. There is no need to replace it.

There is no real gain using SCSI over IDE if you use some old noisy 730 MB (just a guess) hard drive. Your board could run into the 504MB limit with an IDE HDD though but updating the BIOS to the latest version likely solves this issue if it should arise, at least for drives up to ~2.1GB. I have not had much luck with Asus Socket-3 motherboards and IDE drives larger than that even if drives up to 8.4GB shoud work in theory. Another choice is using a somewhat newer and less noisy SCSI drive, then you won't have to worry about BIOS updates but finding a suitable (as in not noisy) drive is not very easy. You can also look into Compact Flash cards or DOMs but the same limits apply for those as with IDE drives, another thing worth looking into is disk overlay tools.

Asus still hosts the BIOS and manual for this motherboard but not the correct BIOS flash tool from what I could see so I'm attaching everything here. This is not only for you but for future use aswell, Asus could stop hosting the BIOS and manual at any moment. You can thank member vetz for the BIOS flash tool as he uploaded it in another thread but it can be good to have everything in one place. If you flash the BIOS be sure to read the instructions as it involves making sure the jumper for 12V or 5V flash programming voltage is in the correct position. Trying to program a flash chip that uses 5V programming voltage with 12V will destroy the chip so you need to pile the sticker of the BIOS chip, check what model it is and Google the correct programming voltage.

The manaul for the Asus PCI/I-486SP3G.

The latest BIOS for the Asus PCI/I-486SP3G.

The correct BIOS flash tool for the Asus PCI/I-486SP3G.

Instructions covering how to flash the Asus PCI/I-486SP3G BIOS.

This board also supports the AM5x86/133 and these processor are pretty affordable:

Set jumpers as follows:

18 1-2
20 1-2
Non-SL
33 2-3
34 2-3
35 1-2
36 2-3
38 open
40 2-3

The L1 cache must be run in Write-Through mode since the Saturn chipset doesn't support Write-Back mode for L1 cache. Jumper 36 controls the L1 Cache Mode. The BIOS setting for cache refers to the L2 cache.

- CPU external clock: 33MHz
JP18 1&2
JP20 1&2

CPU SL selector: non-SL
JP30 2&3
short JP31:pin1 with JP32:pin1

- A x2 setting will tell the AMD-X5-133 to quadruple

CPU internal clock selector: x2
JP33 2&3

Great! I will try to organize a AM5x86 from somewhere and test.
I also found my old Gravis ultrasound classic. hopefully it will work. I might install this one in as well with another co- soundblaster or so.

does someone has experience with the aztec Monster or scsi2sd in retro-pc`s ? how is the Speed compared to proper scsi drives?

Sounds like you have the makings for a nice retro setup! Congrats! I can't answer your other questions but I'm certain someone on here should be able to help! Welcome to VOGONS!