Those would be the recommend timings to run at the rated speed(DDR500). In order to reach this you would need to overclock. You might try running tighter timings at lower voltages if you want faster speed at DDR400. For example from 2.8v to 2.6v and 3-4-4-8 to 2-2-2-8. Make sure your familiar with clearing the cmos(bios setting reset) before starting.
The ? represents the CPU multiplier. The reason why there is a question mark there is because different cores use different multipliers at stock. For instance my my socket 754 3000+ uses a 10x multiplier(base clock 200mhz X 10=2.0ghz). A 2800+ uses a 9X multiplier(200mhz X 9=1.8ghz).
Since the memory controller is on chip when you increase the base clock the memory clock scales up as well. So in order to get your ram to run at it's rated speed you would need to increase your base clock. It will be at 200 by default. Increase to 250 and your ram would run at 500mhz. There are other things to consider when doing this so read up on overclocking first.