Being an overclocked Pentium III-S user, I'm quite interested in your system. Did you need to mod your BIOS in order to support the Tualatins on your motherboard? In my case I have a native Tualatin motherboard, a QDI Advance 10T, running a pin modded CPU I bought from the renown South Korean ebayer. I managed to raise the FSB through software (CPUFSB, as there's no way to do it through BIOS) up to 147MHz and runs stable, but if I go beyond I start getting BSODs and random freezes. I mostly would be interested in the CUV4X if it lets me use the Tualatin without having to tamper with the BIOS and if it lets me overclock straight from it, rather than using CPUFSB in Windows. The graphics card I use in my case is an overclocked ATI Radeon X1950 Pro, works like a charm, the entire system is very fast and snappy. In my case I run my RAM (x3 Infineon PC133 CL2 sticks) at CAS2 Turbo mode.
I highly recommend you to put an X1950 Pro on that system, overclock the card to the maximum stable limit, and you'll get quite a speed demon. 😎
My Retro Daily Driver: Pentium !!!-S 1.7GHz | 3GB PC166 ECC SDRAM | Geforce 6800 Ultra 256MB | 128GB Lite-On SSD + 500GB WD Blue SSD | ESS Allegro PCI | Windows XP Professional SP3