I'm almost SURE That Turbo changes some settings if everything is set to auto.

On the old BX chipset, Turbo and F1 and Speedracer, besides standard, were the settings available, and each one affected certain subtimings that you couldn't change manually. But those worked with manual cas latency settings; setting F1 stopped my board from booting at any higher FSB. Pretty sure Turbo does something similar here; maybe related to auto settings, probably unimportant. I never saw any difference with a 65nm cpu, at least with 1M spi....