I don't think it's dangerous, and generally just try +20%. If it fails, I'll get a Blue Screen of Death, and try again with +10%. If that don't work then I take it back to the shop and claim it only works if underclocked
There are two groups of overclockers - those that come home from work and drool over benchmark results (overclocking new hardware) ... and those who come home from work and need more power in a 3D game (overclocking older hardware).
I don't think it's a minimal gain at all. If that was the case, why do they sell faster processors?
Use overclocking as a (risky) alternative to upgrading. It's not free though because you will probably need to invest in improved cooling.
The processors all come off the same production line, but due to manufacturing methods, no two chips are identical. They are all tested and grouped by stable working frequency; some get binned. When it comes to selling them, you can get lucky if the manufacturer had very high gains - because that means they sold off high-spec processors as lower spec to make up numbers. Whoohoo! Checking the location of where they were manufactured can increase these odds because not all factories are equal.
However, if all goes horribly wrong, they can burn out
You may also be able to tweak the voltage, but I'm not familiar with current motherboards so cannot be sure if that's an option. Electric signals in processors can be damaged by electronic noise (often caused by heat) - causing a crash. Higher voltage gives a stronger signal. Lower voltage reduces heat.
Note that heating problems can affect any computer. Older machines will sometimes overheat because of too much insulating dust clogging up the CPU fan or coating the heatsink. An overclocker just needs to be more aware of such things and keep the cooler nice and clean - and replace worn out fans
You can also overclock your
graphics card. This is not likely to produce massive performance gains because they are actually rather CPU-dependent. PC architecture is fundamentally flawed. Bah. I don't like to overclock graphics cards but some manufacturers assume their customers will do so. They use memory chips rated higher than factory settings, or add cooling where none is required. Like the chips on my GeForce3 are rated to 250MHz but are clocked at only 230MHz (460DDR). Checking online reviews will often expose these details for you without the need to rip heatsinks off and take a look for yourself.
System memory can be overclocked, but I think that's a really bad idea, because memory chips are normally sold with minimal redundancy - meaning they are running close to the bone as it is. I have overclocked the memory bus at times but only with higher-rated memory chips already seated.
One that really improved my 3D games was overclocking the
mouse! You can actually increase the frequency of the PS/2 mouse port to increase the number of updates per second. I have done this with excellent results. The mouse does actually need to be high quality or it will malfunction
Basically anything can be overclocked. The PCI/AGP bus can also be done to increase the speed at which data travels between the graphics card and CPU. This generally has severe side-effects on unsuspecting devices like network cards - manufacturers of such things rarely think of accomodate overclockers
For a wonderful database showing overclocking results for each processor model, visit
http://www.overclockers.com - I have always achieved what is given here as the "average overclock" using only regular air cooling.
For a catalogue of CPU coolers (which can influence your purchase even if you aren't in the UK) see
http://www.overclockers.co.uk - I'm not sure if they still do, but they used to sell processors tested & guaranteed to overclock
Serious overclockers in search of maximum benchmark results (which is kind of a hobby to them) will resort to watercooling or the use of a peltier. This increases the cost so is rarely worth doing with older computers - though the peltier might tempt you. A peltier is a heat-plate, except one side gets cold and the other side gets extremely hot. You put the cold side against your CPU and invest in truelly awsome cooling on the other side. With such a setup you might achieve +50% or more. Some people will even use water cooling on their graphics card
A peltier
must produce more heat than the overclocked CPU - or it won't be able to cool it. The cooler, whether it is air or water, must be able to get rid of that energy - and not just leave it trapped in the case! There will also be condensation around the
frozen CPU which requires attention and nerves of steel.
Note: I have never used watercooling, and only planned peltier cooling with big extractor fans. Leaving the case panels off does not work as well as you might think because the air is not being moved, meaning it stagnates and just warms up. A sealed case with well planned air-in/out will shift heat more effectively.
In the run-up to the 1GHz milestone (some years ago) there was a company that sold, in the UK, a 700MHz Athlon (@ 1GHz) in a case with a fridge and water cooling. This was a regular highstreet product in competition with Dell and others. Funny, no?
One last final note, back down to earth: You will get better results if your PC is not next to a radiator or in direct sunlight. If you live in Canada, just wrap your PC in a plastic bag and hang it out the window
.
