I am no expert but I don't think this will help you to the point that you will even notice it. Yeah the timings in the bios will always default to your slowest timings (i.e. the ram that is 5-5-5-18).
Anyway to answer your question, there are two ways to overclock your ram. Speed (MHz) and timings and they are both dependent on each other. The more you increase the speed of the ram the bigger the timings will need to be. So one way to do it is leave the speed at its current speed (probably 800MHz?) and then try lower the timings one at a time. I don't know how much you will be able to drop the timings by though. You will have to do some research on overclocking your specific ram.
Are you ever using 100% of your ram capacity? That could be one problem. A fresh install of windows will also help speed things up. Try resist the urge to install loads of crap on your machine (we all do it).
Put up your full system specs incl hdd with size, what you use the pc for, how much is installed on it etc. We might be able to help you speed up your PC a little more. What anti virus do you use as well? Some can really slow a PC down. Microsoft Security Essentials is decent enough and doesn't interfere with your pc too much.
ok... well i just did a fresh install for a 64bit.
this computer even though it is old, my gf plays a lot of games on it and it takes a lot of resources.
some games are 2gb some are 4gb recommended. the games run on max graphics that they can, so i assume that there really is not much ram left over for the system (meaning that all 5gb are probably used or close to)
thanks for the reply... you know maybe ill just disable some un needed services in bios, and OC just the cpu and try it out like that.
for me the ram thing is very complicated, because even i found a specific guide to my motherboard, but bios version is different from the guide so there are different options/settings (mine is up to date)
ive got 2 HDD in there, system and files. so thats ok. no anti-virus, just some basic system cleaners (only 1 runs all the time) and malware programs