How, exactly, does overclocking work?

john01dav · December 2, 2018

I have an old FX-8350 system that I want to try to squeeze some more performance out of with overclocking. To do this, however, I feel like I need to get more information about overclocking. I know that a faster clock speed generally means more performance on the same specific CPU, that greater voltages produce more heat but also allow for faster clocks, and that a voltage of too high can cause permanent damage to the cpu. I do not, however, have any idea (other than < 2V) for what sorts of voltages are safe to run, nor really what temperatures are safe to run. I expect that different people have different opinions about this, but that doesn't mean that there isn't objective data that I can use. As such, I would like to as for a link to a fairly comprehensive guide from a reputable source (ie. video(s) from LTT or similar youtubers) that goes over all the relevant information in detail in a way that is applicable to a wide variety of CPUs.

r2724r16 · December 2, 2018

9 minutes ago, john01dav said:

As such, I would like to as for a link to a fairly comprehensive guide from a reputable source (ie. video(s) from LTT or similar youtubers) that goes over all the relevant information in detail in a way that is applicable to a wide variety of CPUs.

bellabichon · December 2, 2018

I'll try my hand at explaining. Feel free to correct me if i'm wrong about anything.

Overclocking, in a nutshell, is tweaking your system to run faster than the manufacturer recommends. For example your CPU, the FX-8350, has a recommend base speed of 4.0GHz, with a boost speed of 4.2GHz. This threshold is set by the CPU manufacturer, and every FX-8350 off the shelf is guaranteed to achieve that speed. However, silicon chip manufacturing isn't a perfect process. Because of small, almost microscopic imperfections in the surface of the silicon itself, some CPUs are able to run at higher frequencies and voltages than the manufacturer recommends. This is called the "Silicon Lottery" because there's no way of knowing how an off the shelf chip will perform without testing it. For example, the 8700K is designed to run at 3.70GHz base on all 6 cores, with a boost up to 4.70GHz under heavy load. However, if you're lucky, you can manage to make it run at 5GHz on all 6 cores, by increasing the voltage and clock speed. To make a CPU run quicker, you generally need to give it more power to work with. Most CPUs, by default, run at a voltage of around 1.35V. When overclocking, you might need to raise that up to about 1.45V for your system to be stable, but any more than 1.5V is playing with fire, and you could fry your CPU, along with all your other system components. Do some research on YouTube and on other forums, but the basic process is almost always the same. Enter your motherboard BIOS, and slowly increase the core clock. If you machine becomes unstable before you've achieved your target frequency, slowly increase the voltage until it's stable. When you've achieved your goal, stress test it under heavy load (i.e Aida64) for about 30 minutes to 1 hour to make sure it's actually stable. Just remember, more voltage means more heat. You're going to need adequate cooling, especially on older AMD chips like yours.

Hope this was helpful. Again, anybody should feel free to correct me if I got things wrong.

EDIT: Just saw the part about you not knowing much about CPU temperatures. It's pretty simple. With average cooling, your CPU should be hovering at about 30-40C at idle (not doing any strenuous tasks, windows desktop or maybe some light internet browsing.) Under a heavy load, (either a synthetic stress test, or a real-world situation, like playing a game) your CPU generally shouldn't get hotter than 90C. If it is, you're either pushing it too hard, or you might have a cooling problem (i.e. bad thermal paste application.) CPUs are generally designed to run very hot, but performance will suffer. Most CPUs will also Thermal-Throttle (automatically turn down voltage to reduce temperature) when they get dangerously hot.)

EDIT2: Higher frequency doesn't always equate to faster CPU. For example, your FX-8350 has a higher base clock than an 8700K (4.00 vs 3.70), but it's obviously not faster. This comes down to amount of CPU cache, core/thread count, and size of the manufacturing process.

Hope I could help. Good luck!

Edited December 2, 2018 by bellabichon
More information/clarifying.