Thursday, August 18, 2022

What you need to know about overclocking processors


Overclocking processors is one of the most affordable ways to increase the performance of a workstation without an impressive financial outlay. However, beginners often do not understand how to approach this matter and worry about the performance of the system if overclocked incorrectly. In fact, basic “overclocking” is fairly easy to pull off with the right level of hardware.

Where to start
It should be noted right away that almost all processors from AMD ( Ryzen or FX) are overclockable, while Intel will have models with the “K” or “X” index (for example, Intel Core i9-9900K or Core i7-9700K ). Also, overclocking requires a motherboard with a suitable chipset.

Without going into details about the chipset design, we can say that to overclock Intel, you will need motherboards with a chipset marked “ Z ” or “ X ” (Z99, Z390, X99, X299, etc.). For “overclocking” processors from AMD’s Ryzen family, any AM4 motherboard socket on B350 , B450 , X370 , X470 or X570 chipsets is suitable . The exception is the A320 chipset, which does not support overclocking AMD processors.

The principle of overclocking any processor
Each processor is made up of multiple cores that run at a specific clock speed, measured in GHz (MHz). This value shows the number of processor cycles per second and is obtained by multiplying the processor multiplier by the bus frequency (a kind of trunk channel that provides interaction between the processor and the chipset). Bus frequency today is a constant value. Thus, we get the base frequency of the processor (or the frequency of all cores), for example, the Intel Core i3-9100F processor , according to the characteristics, has a base frequency of 3.6 GHz, that is, its base multiplier is 36:

36 (multiplier) x 100 MHz (const bus frequency) = 3600 MHz.

In addition to the basic frequency value, almost any modern processor has a high performance mode (Turbo Boost), when the multiplier automatically changes, overclocking the processor cores. For the same i3-9100f, this value is 4.2 GHz, that is, according to the formula, the processor multiplier in the load changes to 42, instead of 36.

The principle of overclocking processors is to increase the processor multiplier by a value greater than that set by the manufacturer, thereby increasing the clock frequency of the processor cores or increasing system performance due to more operations processed by the processor per second.

However, everything is not so simple. For each processor, there is a certain frequency threshold that it is not able to overcome without the threat of core degradation. This threshold is determined by the voltage and the corresponding temperature.

Features of processor power consumption
In order for the processor to operate at higher frequencies, it will require increased power consumption, that is, an increase in voltage. In this case, the temperature of the processor will increase exponentially. As a rule, processors from AMD or Intel start to overheat and, as a result, turn off or skip cycles to cool down a bit, at around 85-95 degrees Celsius. This is the main, limiting factor in overclocking processors.

Typically, the voltage of processors is in the region of 1.2 V–1.3 V. At such values, the cooling system is able to dispel the heat generated by the processor, allowing the system to work stably. For overclocking, you will need to increase the voltage above these values, but it is highly undesirable to set it above 1.45 V, especially with a weak cooling system.

Thus, the whole overclocking process consists in finding the “golden mean” between the maximum processor frequency and the minimum voltage (and, accordingly, temperature) necessary for stable operation of the system at a given processor frequency.

Cooling Requirements
The processor, like any other element of the computer, heats up during operation, so it is necessary to provide the CPU with high-quality cooling. Depending on the architecture, frequency and core voltage, each processor has its own TDP (Thermal Design Power – thermal design power), which is measured in watts and shows the power that the cooling system should be designed for. For example, the Ryzen 7 3700X has a TDP out of the box of 65W. This means that a 95W cooler is more than enough for a non-overclocked 3700X.

During overclocking, the heat dissipation of the processor increases, so it is always worth taking a cooling system with a margin. For overclocking powerful multi-core processors, tower air and two-section (or more) liquid cooling systems are well suited.

Motherboard selection
As already mentioned, when overclocking the processor, its power consumption and the load on the power supply circuits of the motherboard increase. Therefore, for safe overclocking, it is recommended to select a board with high-quality power elements.

If you wish, of course, you can overclock even on the most entry-level board that has a 4-pin processor power connector and 3 power phases. The main thing is that the BIOS should be able to change the frequency settings. However, such experiments can end in failure, because in this mode, the iron works “for wear”, and it is not known how long it will live under increased load.

Processor power
4-pin is suitable for powering processors up to 120 watts. The computer will continue to work even at higher power consumption, but excessive load will adversely affect the state of both the power supply and the motherboard (4-pin can simply melt and burn out). Four 12 V wires have twice the cross section as two, which increases the load capacity of the cables.

It is worth noting that even a board with 8 + 4 connectors can be powered through a 4-pin connector, and everything will work. The increased number of contacts is only intended to reduce the load on each element and, consequently, heating. Therefore, for overclocking, you need an 8-pin CPU connector, because it is enough for any processor from the mass market segment. Fortunately, in 2020, most power supplies have an eight-pin connector.

Power phases
The processor power system on the motherboard must be suitable for overclocking. Since 12 volts passes through the 8-pin connector, and the usual voltage to the processor is 1.2 V–1.3 V, an element is needed that corrects the power supply of the processor. This role is taken over by the VRM (Voltage Regulator Module). With its help, power is supplied to the processor with the necessary parameters.

The multi-phase VRM device reduces ripple and stress on the electronics, which positively affects the operation of the power system. Information on the number of phases can be found on the website of the motherboard manufacturer, or by counting the number of chokes. The more phases, the lower the load on each of the transistors in the network, therefore, the lower the total heat dissipation. High temperature affects the resistance of the elements, which negatively affects the operation of the system and may eventually lead to failure of the board.

Cooling of power elements
In order for the power phases of the motherboard to work stably during overclocking, they need cooling. Therefore, when choosing a motherboard, you need to pay attention to the heatsinks located on the mosfets. They must be massive enough to dissipate the generated heat and prevent overheating of the power circuits.

Overclocking process for Intel and AMD processors
When the requirements are sorted out, you can start overclocking. It is worth saying that the principle of overclocking AMD and Intel processors is the same. The only difference, perhaps, will be in the ability to overclock the BCLK bus in AMD Ryzen, i.e. increasing the same constant within 5–8%, but this process is creative and completely optional if there is no desire to accurately adjust the RAM frequency, voltage and frequency of the bus itself.

First of all, you need to go into the BIOS of the motherboard. To do this, start the PC and press the “Delete” key on the keyboard. After that, an interface with a large number of windows will open, but first you need to switch to Advanced Mode. Next, look in the “Advanced” / “CPU Features” tab and disable (Disabled) energy-saving technologies, such as:

Intel Speed ​​Shift Technology
CPU Enhanced Halt (C1E)
C3 State Support
C6/C7 State Support
C8 State Support
C10 State Support

Next, look in the same tabs for the CPU Load-Line Calibration (LLC) setting. This setting has several levels and is designed to control the voltage in loads. It is necessary to choose a level at which the LLC graph will be flat, that is, the voltage in idle and in the load will be approximately at the same level. For different motherboards, LLC levels and their number are different. If there is no graph next to this setting, you should look for such a graph on the Internet for a specific board or experiment manually by running stress tests, checking for voltage fluctuations.

After the primary settings have been completed, you can start overclocking.

In the BIOS, you need to find the “Overclocking” tab (or various variations of this setting, depending on the motherboard). After that, we transfer the multiplier adjustment mode to advanced (Advanced/Expert/Manual). The “CPU Ratio” field becomes available, initially set the multiplier equal to the processor turbo boost frequency (for example, for the Intel Core i7-8700K this value is 4.7 GHz or a multiplier of 47), and also set the “CPU Core Voltage” voltage to 1.2 V It is worth noting that on some motherboards you need to synchronize the multiplier change for all cores: the “CPU Core Ratio” / “Ratio Apply Mode” field.

After that, press the F10 key, the settings are saved and the computer restarts. If the system booted successfully, run a processor stress test (for example, AIDA64) and wait 20-30 minutes. With stable operation and optimal temperatures (preferably up to 90 degrees), you can continue overclocking by increasing the processor multiplier by one until the system stops stably passing the stress test or does not start at all. Then we increase the voltage by 0.01 V. By the way, if the system does not start, and when turned on, the black screen is on, you need to turn off the PC and remove the CMOS battery from the motherboard (or close the jumper), then the BIOS settings will return to the factory settings, and the overclocking process will have to be repeated.


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