I got a similar APTIVA 2134 -A1 and tried to max out the poor SIS chipset's performance. Still facing some annoying trouble. Here are the list shows what I have done till now :
1. CPU: Replace Pentium 133 with 233 MMX and new heatsink with a proper cpu fan. Even motherboard is single 3.3V design but actually it works perfectly. Set multiple jumper as 1.5x to get 3.5 x 66=233mhz. BIOS wont recognize correct cpu info since it suupport upto 200mhz only and it will get 127 error and show mmx cpu 0 mhz in bios info page. But cpu-z , hwinfo shows correct info.
2. RAM and Cache: Install 2 x 32mb EDO ram @ 60ns in BIOS. 512KB Cache. Oringinly it came with 64mb fastpage ram and get 111 mb/s in SpeedSys test and now 166 mb/s.
3. HD: Currently use a 8GB CF card adapter link to IDE port on motherboard. Still can't test sata raid adapter and IDE raid adapter because it will show 1805 adapter resource error when install video card @ top PCI slot. Maybe remove the ROM and let adapter work as a Ultra DMA 133 adapter will fix the issue?
4. Display card: Leadtek winfast S600 Virge/DX 4MB @ top PCI slot. System will crash if install video card on lower PCI slot when execute any DX game or test no matter it was 3D or 2D. I got one Matrox G450 Dualhead PCI first but it wont start POST if SIS6205 was disabled. and Every time I tried to install G450 driver system will hang up at last moment. SIS6205 shares memory bandwith therefore affect system performance negatively. When desktop set to more than 256 color, cpu-z benchmark will drop almost half.
5 OS: WINDOWS98 LITE from Oreg. DX8.1 installed.