Specifics of Overclocking on Asus Mainboards

There is a certain algorithm of actions that you need to stick to ideally, when you test a mainboard’s overclocking potential:

1. Find the maximum base frequency;
2. Find the highest CPU clock frequency;
3. Check the effect of different technologies and optimizations, such as Turbo Boost, power-saving, etc.

I have to confess that I messed up the testing plan above. I believe you are mostly interested in the first two plan items, just like me. However, I do not doubt the ability of Asus P6T mainboard to overclock processors. Of course, it can overclock, all we need to do now is find out specific numbers. But if the board can overclock processors and retain all Intel processor power-saving technologies and how far this overclocking can go, this is a much more interesting question, IMHO.

The thing is that there is an old problem about Asus mainboards that the company has known about for a long time, but for some reason doesn’t hurry to fix. When you overclock processors by raising the base frequency or FSB frequency on previous-generation chipsets, all processor power-saving technologies do work as they should for a while. They lower the processor clock frequency multiplier and core voltage in idle mode, thus reducing the power consumption, heat dissipation and noise. At some point during further frequency increase “smart” Asus mainboard decides that the CPU can no longer work stably and increases its core voltage. As a result, next time the system will go idle, the clock frequency multiplier will still be lowered, but the Vcore won’t: it will remain increased. However, as we know it is the core voltage that is most crucial for the CPU power consumption and heat dissipation.

So, what’s the big deal, you may ask? Asus mainboards only increase the processor Vcore on their own, when the corresponding BIOS parameter is set to Auto. Just set the numbers manually, choose the nominal voltage setting for the CPU and you will avoid this excessive and unnecessary voltage increase. True. The Vcore will not increase any more, but the problem is that it won’t be lowering either. Once you set the processor Vcore manually on an Asus mainboard - even if you set it below the nominal – Intel processor power-saving technologies will stop working. The CPU clock frequency multiplier will be reduced, while the voltage won’t.

I have to admit I am pretty frustrated with this issue of the Asus boards. How can the board know for sure what my CPU is capable of? I work hard on finding out the potential of my CPU to make sure that my system will work in the most optimal and efficient way from all standpoints. Once there is significant workload from games or computational tasks, the system should boost its forced to the maximum to ensure the fastest processing. But in idle mode when I am typing or reading, I don’t need super-high speed. This is when the frequency and power consumption should go down, in order to also lower the level of generated noise for more comfortable working experience. Unfortunately, Asus mainboards do not let me do it that is why I haven’t used an Asus board in my home system for a while already. They fit best when the CPU works in the nominal mode or is slightly overclocked. If you have an Asus mainboard for Intel platform, you can check it yourselves. I tested boards on all chipsets starting with Intel 975X Express. Maybe this problem goes back to i945 or even older chipsets, but I don’t have any solutions like that at my disposal anymore.

It would be really sad, but not too frustrating, if the problem existed on any mainboards built around Intel chipsets. Luckily, it is not the case. Abit mainboards, for instance, used to be ideal in this aspect and the best example is the legendary IP35 Pro. Even if you increased the processor core voltage during overclocking, the mainboard would still lower it in idle mode. Not to where it used to be in the nominal mode, but in proportion to the Vcore increase. As a result, the system remained stable and energy-efficient in any operational mode, even during maximum processor overclocking. But Abit mainboards are long gone, unfortunately, and looks like ideal overclocking is no longer possible these days. Let’s see what the other manufacturers’ solutions act like in this case, for example, Gigabyte mainboard that is going to compete against our Asus P6T today.

At first glance, Gigabyte mainboards work just like Asus ones. They will also increase the CPU Vcore automatically during overclocking, if they consider it necessary and the corresponding BIOS parameter is set to Auto. And the processor core voltage will no longer lower in idle mode, if you set it manually at a certain level. However, Gigabyte mainboards have the magic “Normal” setting for every voltage-related parameter including CPU Vcore that will prevent the smart BIOS from acting on its own. Yes, Gigabytte mainboards are still far from the universality of the Abit boards (for now), because if you increase the CPU Vcore the processor power-saving technologies will stop working and the voltage will no longer get lower in idle mode. However, thanks to the “Normal” mode you will be able to overclock your CPU as much as it allows you without increasing its Vcore, and all power-saving technologies will be up and running just fine.

When we overclocked using Gigabyte GA-EX58-UD5 and GA-EX58-Extreme, our Intel Core i7-920 CPU with 1.225V nominal core voltage remains stable up to 181MHz base frequency (133MHz nominal base frequency). It is important to enable “Load-Line Calibration” parameter that will prevent the voltage from dropping under heavy load. If you are using Turbo Boost technology that increases the multiplier to 21, the resulting CPU frequency will be 3.8GHz. I believe it is an excellent result, and considering that we didn’t touch the voltage it is absolutely brilliant! So what will Asus P6T mainboard respond with? Unfortunately, only 152MHz. You will be able to enjoy increased performance on your Asus P6T without losing any of the power-saving benefits up to 152MHz base frequency. The moment base frequency reaches 153MHz+ all Intel processor power-saving technologies will stop working and the core voltage will no longer get lower in idle mode.

As you can easily calculate, at 152MHz base frequency even with enabled Turbo Boost and increased clock frequency multiplier of 21 the resulting CPU frequency will be only about 3.2GHz. I would say it is a defeat compared with the 3.8GHz that our CPU sample is capable of reaching at its nominal voltage setting without losing stability.

Unfortunately, nothing changed with the launch of the mainboards based on new core logic sets. Asus still doesn’t want to fix this issue. It is especially unusual, because Asus Company has always cared about energy-efficiency and environmental friendliness. There is even an entire site, which name speaks for itself: Green Asus. And there is more than just words to these initiatives: the company switches from polymeric to more nature-friendly cardboard product packaging, cares about recycling, provides mainboards with energy-efficient technologies… However, the well-promoted Asus EPU technology that lowers the number of active phases in the processor voltage regulator circuitry in idle mode doesn’t work during overclocking, so when it works it only saves 3-7W of power, while tens of watts of power go to waste during CPU overclocking on Asus mainboards. However, we are going to talk about specific numbers in relation to power aspects a little later in our review, and now let’s find out how far we can overclock processors on Asus P6T mainboard.