skew adjustment (timing delay),settings?

I read that these adjustments could help me stablize my system when overclocking.I can adjust in my bios CPU skew 50ps-750ps(50ps steps),Chip 50-750 (50 steps),PCI 100-1500 (100 steps),AGP 100-300 (100 step).How do these setting effect my system ,where do I start (setting wise),and some if this , then that ,settings would be helpful.????????