you will know that you can lower the mult by trying to lower it in bios and seeing that it works by using wcpuid.
as for ram timings you are talkin about i think you are a bit confused

the numbers like 5:2:1 are the pci divisors which tell what speed the pci cards are being divided by when overclocked.
the fastest ram timings are 2-4bank-2-5-2-2-1t command. there are numerous options in the ram segment in bios and if you set it to those your ram will run the fastest. since you have 2100ram make sure you increase the ram voltage when overclocking from 2.5v to atleast 2.7