Over Clocking PC computers
When overclocking a PC, the main thing you are doing is trying to get more speed for the same price. So the more you can do on the cheap, the better off you are. I have found a few tricks over the years and present them here with any Caveats I can think of.
Refer to the picture to the right for the placement of fans and fan ducts. A fan on the top could clear the trapped hot air in the case. The back shroud (just visible at the rear) separates the hot power supply out air stream from the cooler incoming air nearer the floor. The duct for the back of the case would connect the CPU fan on the motherboard to the back of the case where the round vent is shown. Since there are many styles of cases, your mileage may vary ( that's a joke son).
Note that you can use all or some of these techniques and variations and combination's to get the temperature down when under heavy loads.
Here are some cost effective ideas for cooling
1. The primary problem with overclocking a well designed CPU (a bad design just wont overclock) is heat. That is why over clockers use water cooling and extremists use liquid nitrogen. For the poor guy who can not afford that we need to get creative. My first suggestion is look at your case and Mobo and determine where the heat flows with an eye to re-routing it. We want to get the hot air out and the cold air in. Heat rises naturally so make use of that. Stay away from the cases that put the power supply at the bottom. There is a reason they have been at the top, to suck the heat out of the case at its high point (and hottest). More fans means more heat flow (hopefully out of the case) but it also means more noise. Fans deep inside the case, like the CPU fan make less noise out side the case, due to attenuation and sound dampening. Slower fans make less noise but cool less effectively. These compromises and what you need to look at.
Putting the case on the floor is usually the coolest level in the room. Shrouding the case in a corner or worse, a closet is the worse. Air flow to carry away the heat is not there. Direct sunlight in summer is not good either. It is probably a good idea to get a good temperature monitor program and see what happens. Look on the4 internet, there are many good free ones. Many motherboards provide you with one. And the heat comes from work so load the CPU down when looking at temperatures.
2. A primary method I use to get the maximum cool air to my CPU is just cut a hole in the case right above the intake fan. Many cases come with a fan hole in the back that points right at the CPU. Make a cardboard duck to route the cold air to the CPU (see picture above). Put another fan to help pull more hot air out of the case, preferably near or at the top (see picture) where it is hottest. Be sure not to let the hot power supply output air go right back into the CPU input. Make a cardboard baffle to divide the airflow routing the hot air up, if possible. On some, I make a smoke stack stick out of the case to get fresher air. On any duck, the air is restricted and the cooling is reduced. I proved this by running a Mobo on the bench and loading the CPU and letting it come to a constant temp. Then Put a smoke stack on it, just a tube the size of the fan and the temp goes up a degree or 2. If I make the smokestack come shaped, getting bigger as it leaves the fan, the temp drops but does not reach the original temp till it is so big as to make it useless in most cases. So taper the cone as best you can but always make it the size of the fan at the fan and as big as you reasonable can at the other end.
3. To get creative (and use things you may have laying around), you can go pretty wild. Some guys report using Window Air Conditioners and modifying them in numerous ways to get the cold air. From ducks to building right into a computer case or building the computer in the AC unit. Other ideas use not only water cooling with home made water blocks but ice chilling the water. Yet another method is Peltier plates. Pump electricity in and one side cools, the other heats (lot of work here getting rid of the extra heat). You can look all these up on the internet for more info. I have not tried any of these exotic methods but I came up with my own idea that I may try some day. If you have ever used an air compressor, you know they get very hot when compressing and the air is quite cold when it comes out. This is simple high school physics. So what if you had a compressor out side with a hose coming in the window to your computer. A small hole letting the air out and pointed at the place you want to cool should do the trick. Lots of trial and error would be needed to determine the most efficient approach but I see no reason it should not provide effective cooling to any temperature you want down to about freezing, in theory. You can make frost form with an air nozzle directed at a small thin object.. Remember that frost and condensation are your enemy as much as heat. Many of these methods may not be very practical economically, acoustically, ecologically, or efficiently but this is mostly experimental and hobbyist.
Now lets look at other things you can do to over clock
4. Bang for the buck is my game so I will point out a few tips in that vain. The top of the line CPUs are usually hand selected at the factory and get top dollar. And they are by definition, the best there is. So there is often little room for over clocking them. The best bang is to pick the slowest of the bunch after they have been made for a year. Because the slowest are often rejects, as time goes on, the process gets better and the slowest Can actually run far faster but they need to keep selling the slowest because of contracted quantities so they just sell the faster versions at a "loss". For fairly new items, chose the mid stream models as these usually have good yields and considerable headroom. This is even more true for RAM. Mid-range RAM can always run faster than stated and cheapy RAM is hit or miss. I always buy it and only about 30% of the time am I disappointed.
5. Here is a trick I recently tried that seems pretty neat. When the CPU makers need to get the last buck from the poor yields of there manufacturing process, they often turn off features that don't pass there tests and sell these devices as a lower class of device. The best example I can think of is the 3 Core CPU chip. There was never a design for 3 cores at Intel or AMD but a significant percentage of 4 cores did not pass the tests on one CPU core so they sell them as 3 cores with one turned off internally. There are some folks that found a way to turn on the dead core and seem to have a good chance of getting 4 good cores for the price of 3 (see 4 above for a reason this can happen). But here I am talking about the overclocking of the 3 core. The chip was made to dissipate the heat from 4 and only gets the heat from 3 so it is inherently a strong over clocker. And since they are basically rejects, they are sold very cheap. Hardly more than a dual core. If you can get the Black or engineering sample versions, these are great. I overclocked my black 3 core from 2800 to 3800 with a cheap $25 heat sink (and the tricks above).
If you have AMD 4cores, you can do somewhat the same thing using the AMD overclocking software and just speeding up 1 or 2 cores and slowing down the other 2 or 3. This would give you a fast 2 core or 1 core with a little boost from the slow cores running the operating system. Many programs are single thread so this works very well for them. All the games except the most recent are single thread.