Overclocking 1.6 & MSI645

I've got a MSI 645 ultra and P4 1.6. I tried Fuzzy Logic3 and ran the fsb at 126mhz which in turn pulled 2.1Ghz, anything more and crashola. So I went into the BIOS set the multiplier@16, CPU/DRAM 3/4 so the mem was at 166mhz, fsb 126, AGP ran at 80mhz and the PCI@40mhz, [email protected]. I save it reboot and it works ok. Once again I increase the fsb and reboot and my screen takes longer to come on and the lettering is all faded. The temp stays under 45C. Is it that my AGP/PCI multipliers need to be changed. I looked in BIOS and see nothing to do this. The video card is an nvidia MX420. Any solutions?