These motherboards usually use 72-pin FPM (70 ns) or EDO (60 ns) RAM. You should use them in pairs. And all of the modules should use the same timing (60 or 70 ns). There are special modules (50-20 ns), but these are very expensive and rare, too. And I'm sure your mobo won't be able to use them. Most of these mobos can use SIMM modules up to 32MB. But there are 64MB modules too, you should use them if your mobo supports.
Newer (mostly ATX) mobos can use SDRAM, too.

Most of them can use DIMMs up to 64MB. Some of them can use 128 and 256 MB modules too, you should see the manual of your mobo.

WARNING: The memory speed will be 66Mhz. Be very careful when buying any modules.
I have a Cyrix MII-PR300 (quite good, it's like your processor). I haven't got any AGP, too. So I use an S3 Trio64 (2MB) video card and a Woodoo II (12MB) 3D accelerator. They work well together, I can play Re-Volt, Disciples II, Celtic Kings, Colin McRac Rally 2, and other games.
But there are many PCI 3D cards, you shuold buy one. Their price is about 10-20$.
One more: these mobos can use hard drives up to max. 8GB (usually
8.000.000 Byte

). If you want to use bigger hard drive, you should create and format a max. 7GB partition for the OS, and an extented partition with logical drives ON AN OTHER COMPUTER whitch can handle bigger hard drives. After that you will be able to use your winchester, Win98 (and up) are able to handle these hard drives.