I heard about this overclocking thing for computer componintes. How do I do this?
Basically the components work by a centralised clock which keeps things coordinated. A design engineer will make a reasonable clock speed decision based mainly on thermal factors. Heat is the basic problem in all computers.
Then sales gets involved. Although the cpu is designed for a high clock speed when the cpus come off the line not all of them are capable of running at the maximum speed. So the fastest cpus get sold for $x but the other cpus may still have a market at $y. Now with marketing involved cpus that could be grouped in the fastest group may get sold as substandard or other because of marketing factors. Also as the engineers get better at making parts so the yield of high performance cpus may increase.
So some people noticed that their "substandard" cpu could be run at the higher clock speed. That's probably where it all started. In this senario basically all the components are running within the design envelope but the cpu has a conservative speed stamped on it. The gain is reasonable, the cost here is low but the warrenty is invalidated.
These days people push the limits and try to overclock a cpu beyond the highest design clock speed. Cpu manufacturers put limiters on the cpu to stop people overclocking so they will buy more expensive cpus rated at higher speeds.
If you want to get into this world then have a dig at tomshardware.com. Heat is always a major problem with reliabilty and many computers have problems running Trainz because the cpu is run at 100% for periods of time and the computers are not designed to cope with this. Basically they die after a couple of hours running. Switch them off and let them cool down and normally they come back to life. This is the reason in the hardware sections of the forum you'll see recomendations of ASUS motherboards, specific cases and extra fans. Specific motherboard manufacturers have designed motherboards that help with the HEAT problems. Look at the high end gaming machines and you'll see heat pipes everywhere, five fans in the case etc.
So to do this right you need to measure the thermals and put in exotic cooling systems. Water cooling traditionally has been used but get a leak and it's expensive to say the least. Liquid nitrogen is good but not every one is geared upto having it available. These days the best of the air pipes is probably the best solution.
You need the coolest running components you can lay your hands on. So the 45 nm new Inter cpus are a good place to start. Specific cpus are sold as unlocked ie you lose the warrenty but we don't place a limit on the clock speed.
You may wish to read this article
http://www.tomshardware.com/2007/12/13/can_water_push_yorkfield_to_5_ghz/
to get some background.
Some games respond better to overclocking than others "Call of Duty" for example doesn't give a very good return on investment.
The other thing to do is look at the requirements. 24 fps is used to show moving picures in films. I'm not convinced anything faster is discernable by the human eye although it does depend on age. Normally you can reach this level with Trainz by being selective in the layouts for a cheaper price than a liquid nitrogen cooled system. Video cards such as the ATI 3870 may not be the fastest on the planet but they are quite capable of running Trainz at a fair rate of frames per second. Trainz will run on machines that are not quite the fastest ever made and that means more reasonably priced.
So in answer to your question start with high quality components, be prepared to spend a lot of money, and accept at the end of the day you may not get a return on investment that is reasonable.
Cheerio John