You'd need to overclock your E8500 so that the FSB reached the ratio that matches the RAM:
DDR2 800/2 = 400
E8500 clock is 9.5 x 333 mhz = 3.2 ghz
So, if you want it to be 1:1, you need that FSB to reach 400, like the memory.
If you get it there, your new clock become 9.5 x 400 = 3.8 ghz.
That should be a moderate overclock and nothing extreme.
Yes, overclocking is worth the performance - IT'S FREE!
Good luck. Hope that's the info you need.
PS: Read the overclocking guide to help you out - it's got a lot of good info about what you need to do so you don't ruin anything in the system.