Hi and welcome to Overclock.net.
Let's start with something basic for that combination of hardware you have there, so:
I've let all the power saving features on (enabled) so that my CPU even overclocked will consume less energy and therefore the frequency will change from 2.0GHZ
to the full 3.0GHZ
when needed/full load.
I use a 2:3 ratio (which gives me a 1000mhz RAM Frequency) but you should try to run a 1:1 ratio then the DRAM Frequency will read 664mhz or a 4:5 ratio which will be a 835mhz. But the 1:1 should be your first try.
And the timings that you'd need to use are 4-4-4-12(leave the rest of the numbers at the default value) with a 2.20v
Now, if that's a little too high, meaning the temperatures get a little too crazy, like for example 43c for idle and 63c for full load? Then try a CPU frequency of 300 and your RAM should read DDR2 600, always with a 4-4-4-12 and a 2.20v. The rest? at the default values.
Several people in this forum, including myself would highly recommend you get a Tuniq Tower 120
HSF, the temps should considerably be lower when using that instead of the stock HSF. Also some Artic Silver 5 thermal past should help as well.