Editor’s Note: Recently, Xbitlabs published an article about the power change after CPU overclocking, which I believe players will be very interested in. Xbitlabs has quite strong technical strength, and their own power consumption test platform can record the current and voltage values of various voltage outputs of the real PC platform in real time, so as to get the power values in various states.
Bubble net Chassis Power Channel On April 25th, the power consumption of the processor is closely related to its frequency. Overclocked players will consume more power while improving the frequency to obtain high performance. How much impact does overclocking have on power consumption? We overclock several U’s of Athlon II, Core 2, Core i3, Core i7 and Phenom II families to different degrees. I hope this article will help you understand the impact of overclocking on CPU power consumption.
Generally speaking, the heating of Mosfet is proportional to its frequency and the square of its voltage, but in addition to these two general laws, the heating of processor is also related to many factors, such as its architecture, the number of working cores and manufacturing technology. Since there is no general formula to describe the energy consumption of the processor, we will actually measure it.
● Four platforms and nine kinds of CPU power consumption tests.
Our test was conducted on four platforms: LGA775, LGA1156, LGA1366 and AM3.
Motherboard:
ASUS P5Q3 (supporting LGA775, P45 chipset, DDR3 memory)
ASUS P7P55D Premium(LGA1156, P55 chipset)
Gigabyte EX58-UD5(LGA1366, X58 chipset)
Gigabyte MA785GT-UD3H(Socket AM3, 785GX+ chipset, SB750 south bridge)
memory: 2×2GB, DDR3-1333, 9-9-9-27 (Kingston KHX1600C8D3K2/4GX)
display card：ATI Radeon HD 5870
Hard disk:VelociRaptor WD3000HLFS
Power supply:Tagan TG880-U33II（880W）
Radiator:Limin U-120E
Users who want to know the platform we use to test power consumption can refer to here: "PC power consumption: how many watts is enough?In this article, we don’t spend much time introducing this test platform. In short, compared with using ammeter. For voltmeter, our test platform can not only provide more accurate data, but also record the test results in real time. Because the power supply of the processor is not only provided by the 12V CPU interface, but also by the motherboard 24PIN interface, our platform can also measure together.
What’s more, the power we test is the value at the output side of the power supply, while the traditional IT media usually use the power baby socket, and the number tested not only includes the power consumption required by the whole machine, but also the heat generated by the power supply itself.
● overclocking power consumption test of Athlon II 255 dual-core processor
Athlon II X2 255 is the highest frequency model among Regor family dual-core processors, but its price is not high. The default frequency is 3.1GHz, and each core is equipped with 1MB of secondary cache. You can see relevant information in the screenshot of CPU-Z.
Athlon II X2 255 information
The core voltage of the processor is 1.4V by default, and the north bridge chip is built in the processor, and the north bridge voltage is 1.175V According to the official specifications, the thermal design power consumption of the processor is 65W. Under our test platform, the total power consumption of the platform is 11W, and the measured power transmitted on the 12V CPU power supply line is 63W, which is very close to the thermal design power consumption of the processor.
Without pressurization, CPU overclocking to 3.6GHz can still be fully loaded, and Athlon II 255 can work stably at 3.8GHz after pressurization to 1.5V v.
Overfrequency result
At the same time of overclocking, the frequency of the north bridge built in the processor is also increasing, but this has little effect on overclocking. This CPU has no three-level cache, which is why it is better than Phenom II.
System power consumption change
Variation of power supply current in each channel
From the results, most of the loads are added to the interface of 12V CPU (the port of 8PIN/4PIN on the motherboard), and no matter how the frequency or even the voltage increases, it has no influence on the current on the 12V power supply line on the motherboard 24PIN, and there is no change in the requirements of 5V and 3.3V in the motherboard 24PIN interface.
The power consumption increased by 30.5 watts after the frequency increased from the default 3.1GHz/1.4V to 3.8GHz/1.5V; When the frequency is increased from 3.6GHz/1.4V to 3.8V/1.5V, the power consumption is increased by 21 watts.
● Athlon II quad-core processor, the most power-saving quad-core CPU.
AMD’s second CPU is Athlon II X4 635. Although it is also called Athlon, it belongs to aka Propus architecture. It is an inexpensive quad-core processor of AMD and adopts 45nm technology. The default frequency is 2.9GHz, and each core is equipped with 512KB L2 cache, without L3 cache.
Athlon II X4 635
The default voltage of CPU is 1.4V, and the north bridge voltage is 1.175V These are the same as the processor just now, and the official thermal design power consumption is 95W. On our test platform, the total power consumption of the platform is 146 watts when running at full load with the default parameters, which is 35 watts more than that of the dual-core platform just now. The power consumption provided on the 12V CPU power supply line is 96W.
Overfrequency result
Propus architecture of the processor is not good, even if the pressure can only reach 3.5GHz, the default voltage can only reach 3.4GHz.
System power consumption change
Various current changes
The current of the 12V CPU power supply interface is increasing rapidly, and the current of each channel on the 24PIN interface is basically unchanged. From 2.9GHz/1.4V to 3.5GHz/1.5V, the CPU power consumption increased by 41 watts. From 2.9GHz/1.4V to 3.4GHz/1.4V, the power consumption only increased by 15 watts.
● Performance of overclocking 4GHz of Yilong II dual-core processor
In addition to the lower-end CPU outside Athlon, we also chose the processor of Phenom II series, which has dual-core and quad-core. For dual-core, we chose Phenom II X2 555, contributing 6MB of L3 cache, with a default frequency of 3.2GHz, and each core has 512KB of L2 cache.
Phenom II X2 555
Its default voltage is 1.4V, and the north bridge voltage is 1.2V. Because of the three-level cache, the thermal design power consumption of Phenom series processors is higher, which is 80W. In the actual test, the platform runs at full load under the default parameters, and the total power consumption of the platform is 123 watts, and the CPU power consumption is 74 watts.
Overfrequency result
Deneb architecture is very good, usually there will be a frequency of 4GHz, and this CPU is the same. It can run stably at 4GHz after being pressurized by 0.15V, and the maximum is 3.8GHz without pressurization. Because this CPU is a black box version, we only change the frequency doubling when overclocking.
System power consumption change
But this is not the most energy-saving way. After the frequency doubling is fixed, the Cool and quiet function will be turned off. If you want to improve the performance without sacrificing the performance, it is still not recommended to overclock with the frequency doubling function.
Various current changes
From 3.2GHz/1.4V to 3.8GHz/1.4V, the power consumption of the system increases linearly, and it increases by about 2-3 watts per 200MHz. After increasing the voltage, the power consumption increases obviously, and the power consumption of 200MHz between 3.8GHz and 4.0GHz increases by 37 watts.
After overclocking, only the current of the 12V CPU power supply interface increases obviously. The power consumption of the dual-core Phenom II X2 555 is 120W when it is fully loaded at 4GHz, which is 1.5 times that of its default thermal design. However, the current does not increase by more than 10% without pressurization, so overclocking without pressurization is safe even for the motherboard without enhanced power supply.
● AMD’s strongest quad-core processor, with power of 190W after pressurized overclocking.
Phenom II X4 965 is the fastest and most expensive AM3 processor in AMD. It adopts Deneb architecture, but it has four complete cores compared with the dual cores just now. Each core is equipped with 512KB L2 cache, and all cores share 6MB L3 cache. The default frequency is 3.4GHz, which is the highest frequency processor of AMD at present.
Phenom II X4 965
The default voltage is 1.4V, and the voltage of the built-in North Bridge chip, memory controller and tertiary cache is 1.1V. According to different processes, AMD has two versions of thermal design power consumption of this processor, 140W and 125W, and the thermal design power consumption of the C3 version we tested is 125W. However, when the actual default parameters are fully loaded, the power provided by the 12V CPU power supply interface is already 137W.
Overfrequency information
By the way, in the test, we found that the power consumption of Phenom II X4 is almost twice that of Phenom II X2 555. It seems that the main contribution to power consumption is the computing core, and the third-level cache has little effect.
System power consumption change
As I said just now, Deneb architecture is superior, it can reach 3.8GHz at the default voltage, and the frequency will increase by 100MHz after increasing the core voltage of 0.1V, but 4GHz has not been achieved, because only some tests can be run. Because it is a black box version, we also changed the frequency doubling when we surpassed it.
Various current changes
The test results are typical, and there is a linear relationship between power consumption and frequency without changing the voltage. Once the voltage is applied, the power consumption increases sharply. After adding 0.1V voltage, the power consumption increases by 40W, and the increased part is provided by the 12V CPU power supply interface.
When Phenom II X4 965 is pressurized to 3.9GHz, the power consumption has reached 190 watts. You should know how much burden the power supply part of the motherboard needs to bear at this time. If it is to exceed this point, the power supply of the motherboard must be excellent.
● Power consumption performance of Core2duo E7600 pressurized over 4GHz.
Just now, they were all processors in AM3 platform. At the beginning of this page, we will show you the overclocking results of Intel processors in LGA775/LGA1156/LGA1366 platforms. First of all, the Core 2 Duo E7600 was manufactured in 2008 with Wolfdale architecture at 45nm. This series is already a low-end product, but many people still like it because of its good overclocking performance. The default frequency of the processor is 3.06GHz, the front-end bus is 266MHz, and it is equipped with 3MB secondary cache.
Core 2 Duo E7600
Although E7600 is also a 45nm process, the default voltage is much lower than AMD’s. The default voltage of this CPU is 1.275v, and the highest core voltage of other E7600 will not exceed 1.3625V V. Because of the low voltage, we can understand why its thermal design power consumption is only rated at 65 watts. Under the default parameters, the power consumption of the platform is less than 96W at full load, which is higher than Athlon II X2 255. Moreover, the output power of the 12V CPU power supply interface is less than 45W.
Overfrequency information
The external frequency of E7600 is only 266MHz, and overclocking is not difficult. It can exceed 3.6GHz at the default frequency and 4GHz when it is pressurized to 1.5V V.
System power consumption change
The situation is more interesting than the overclocking of AMD processor just now, and the overclocking of pressure is ahead of schedule, so I estimate that the inflection point of the sharp increase of current should appear in advance.
Various current changes
In fact, if we change another motherboard, the curve may change. In this picture, the current on the 3.3V line increases obviously after overclocking. The logical assumption is that the memory controller and the North Bridge use this power supply. The current at the power supply port of 12V CPU has more than doubled to 94W before and after overclocking. But the frequency only increased by 30%.
● Core2 Quad Q9505 saves power than Yilong II quad-core.
The processor of the second LGA775 platform is quad-core Core2Quadr Q9505, which is made up of two Wolfdale cores. The architecture is called Yorkfield, and the secondary cache is composed of two 3MB parts, totaling 6MB. The default frequency is 2.83GHz, and the front-end bus is 333MHz, which is not only responsible for connecting the CPU and the North Bridge, but also for the communication between the two dual cores.
Core 2 Quad Q9505
Logically, the thermal design power consumption of this quad-core processor should be the sum of two Wolfdale. In fact, the thermal design power consumption of Q9505 is 95 watts, which is related to its low main frequency. The most important factor is that Intel chose the core with better power consumption characteristics to manufacture the quad-core processor. At the default frequency, the power consumption of Q9505 platform is only 125 watts, and the power consumption of CPU is only 70 watts. This is another example that LGA775 saves more power than AM3.
Overfrequency information
LGA775 quad-core processor is not easy to exceed, and the air-cooling limit external frequency is 450-475MHz. Because the processor frequency doubling is 8.5X, it can still exceed 3.9GHz after pressurization, and the highest frequency at the default voltage is 3.6GHz.
Because the overclocking performance of Q9505 is good, we choose seven power points. From this, we can see that if the core voltage of the processor remains unchanged, the relationship between power consumption and frequency is still linear. As long as it exceeds 3.6GHz, the increase of power consumption brought by each increase of 200MHz is equivalent to the increase effect brought by the previous 600-800MHz. From 2.8 GHz to 3.6 GHz, the frequency increases by 27%, and the power consumption increases by 19%. After exceeding 3.9GHz, the power consumption increases by 50%.
System power consumption change
Similar to the result of E7600, the current of the 12V CPU power supply interface increases obviously, but the difference is that the 3.3V power supply for the North Bridge also increases obviously.
Various current changes
At the default frequency, Q9505 needs 12V CPU interface to provide 71W of power, 89W at 3.6GHz/1.275V, and it rises to 136W after exceeding 3.9GHz/1.4V, which is not as big as Phenom II X4. We can draw the conclusion that LGA775 saves more power than AM3 platform in both default and overclocking conditions.
● Distributed power supply design makes CPU power consumption difficult to calculate.
In addition to Intel LGA775 architecture, we also have a relatively new dual-core processor with Clarkdale architecture, which uses 32nm technology and has built-in memory controller and display core. Core i3 540 is the mainstream model of Clarkdale series, which supports hyper-threading technology, but does not support turbo-frequency technology. The default frequency is 3.07GHz, and it is equipped with two 256KB L2 caches and a 4MB shared L3 cache.
Core i3 540 information
Using 32nm process can make the core voltage of i3 540 quite low. The default state voltage of the tested CPU is only 1.1V25V, but the built-in 45nm process North Bridge needs additional power supply with a voltage of 1.1 V. Although the latest manufacturing process is adopted, the default thermal design power consumption is still 73 watts. However, the situation is very different during the test. Under the default parameters, the total power consumption of the platform is only 86 watts when it is fully loaded, which is lower than that of E7600 just now. This should be attributed to the simplification of Northbridge chipset into CPU.
Overfrequency information
The frequency of the processor is obtained by multiplying the frequency of the basic clock generator (133MHz) by the frequency multiplication. The overclocking process is very different. The maximum frequency can only reach 3.2GHz without voltage, and it can exceed 4.2GHz when the voltage is gradually increased to 1.375V V. We must increase some voltage for the North Bridge at the same time.
System power consumption change
The picture doesn’t seem to have a rapid increase in current, because we started to pressurize after the second test frequency point. In terms of final frequency, 37% frequency increase brings 50 watts of power increase. This is similar to the amplitude of E7600 and Phenom II X2 555.
Various current changes
The situation of each current is very different from that just now. It seems that the CPU of LGA1156 is not only powered by the 12V CPU interface, but only the computing core is powered by the 12V CPU. The memory controller and other parts are powered by the 12V from the 24PIN on the motherboard. Interestingly, the 12V CPU is not the one that consumes the most power under the default parameters. Unfortunately, because LGA1156 adopts the distributed power supply design, we can’t give the exact power consumption of the CPU.
● The power consumption of Core i7 860 and LGA1366 is similar.
Core i7 860, with 45nm technology and 8MB tertiary cache, supports hyper-threading and turbo technology, although the default frequency is 2.8GHz, which can be automatically raised to 3.46GHz through turbo technology.
Core i7 860 information
In short, Turbo Frequency technology is a technology to increase the frequency as much as possible under the condition that the heat of the processor does not exceed the thermal design power consumption. When the four cores are fully loaded together, their frequency is 2.93GHz.
Because the processor uses distributed power supply, we can’t know the power consumption of Core i7 860. Its platform consumes 155 watts at full load, and this LGA775 platform is much higher. I’m worried that Lynnfield’s processor will consume a lot of power.
When overclocking, we turned off the option of turbo frequency, because automatically increasing the frequency doubling will lead to system instability. We then adjust the frequency of the basic clock generator, and the maximum frequency exceeds 3.4GHz under the default voltage, but Lynnfield is very sensitive to voltage, and finally we exceed 4.0GHz/1.375V V.
Overfrequency information
Platform power consumption change
Before 3.4GHz, the power consumption of the platform gradually increased, and the power consumption increased by 4-6W for every 200MHz upgrade, which once again proved that the default voltage had little effect on the system power consumption. After 3.4GHz, the power consumption increased by 30-40W for every 200MHz frequency upgrade. And we only boost the voltage by about 0.1V every 200MHz.
Various current changes
When it reaches 4GHz/1.375V, the power supply of the 12V CPU connector is close to 150 watts. The total output of 12V has also exceeded 20A, which far exceeds Phenom II X4 965.
● Core i7 950 has been pressurized to 4.2GHz, and its power consumption has soared.
Intel’s LGA1366 platform has a higher positioning. Based on Henalem architecture, we choose the relatively cheap Core i7 950 for testing. It has four cores and is equipped with a three-channel DDR3 memory controller and QPI bus. The PCIE controller of LGA1366 is integrated in the North Bridge chip, not in the CPU like LGA1156.
The default frequency of Core i7-950 is 3.07GHz, and the turbo technology can be upgraded to 3.33GHz, which supports hyper-threading. Each core has 256KB L2 cache, and all cores share 8MB L3 cache.
Core i7 950 information
The default voltage of the Core i7 950 is 1.2V, which is what we first saw. The voltage of the north bridge is also 1.2V, slightly higher than the previous 1.1V.. The thermal design power consumption is 130 watts, and the platform power consumption reaches 190 watts under the default parameters. Although the power consumption is large, it is still quite good, and it can finally be stabilized at 4.2GHz/1.4V, and the default voltage can also exceed 3.8GHz.
Overfrequency information
Platform power consumption change
LGA1366 not only consumes a lot of power under the default parameters, but also becomes more severe when overclocking. When it exceeds 4.2GHz/1.4V, the power consumption is 127 watts higher than the default.
Various current changes
The output power of the 12V CPU interface is doubled. Because the integrated memory controller needs to get power from the motherboard, the 5V current on the motherboard 24PIN also increases. However, the burden of the 12V CPU interface does not increase too much at 3.8GHz/1.2V, which once again shows the influence of voltage on power consumption.
● Finally, let’s summarize the increase in power consumption of these nine CPUs after overclocking.
Power consumption comparison
If calculated according to the ratio of performance to power consumption, silent overclocking is a very good choice, but if performance is pursued and voltage overclocking is added, the energy consumption ratio will be another world. In addition, the power consumption increased due to CPU overclocking. On the Core i7 950, it actually increased by 127 watts, which is a tragedy for most motherboards. <
