Understanding All Voltage Configurations from the Motherboard
By Gabriel Torres on August 8, 2011


Introduction

One of the oldest tricks to increase the probability of a successful overclocking is to increase the voltage from the component you want to overclock. Nowadays, even entry-level motherboards present some voltage adjustments, with high-end models coming with a myriad of them. The problem is that even hardcore enthusiasts have a hard time understanding what each option really means. In this tutorial, we will explain the exact meaning of each one of them in clear language.

The motherboard manufacturers are the ones to blame for this whole confusion. Even though CPU and chipset manufacturers have official names for all voltages their components use, each motherboard manufacturer for some strange reason calls the same thing with different names. Usually, the manual does not explain the meaning of each function – manuals usually simply repeat the name of the function as an “explanation.”(Duh!) The same is true if you ask for help inside the motherboard setup.

Voltage options are changed inside the motherboard setup, which is entered by pressing Del (or F2 on some motherboards) after turning on the computer. But we think you knew this already, since you are interested in a very specific subject.

To understand voltages, you need to understand a little more about how each CPU manufacturer deals with voltages in their product line.

AMD Processors

Processors from AMD make use of the following voltages (the names below are their “official” names, as set by AMD):

The challenge on motherboards targeted to AMD processors is to figure out what “NB” means inside the voltage configuration options. As explained, “NB” can mean the North Bridge (memory controller, HyperTransport controller, and L3 cache, if present) inside the CPU or the North Bridge chip from the chipset. Here are some hints to find out which one is applicable.

If “NB” is written together with “CPU,” “APU,” or “Processor,” then the option is to configure the VDDNB voltage line from the CPU. For example: “CPU/NB Voltage,” “CPU NB Over Voltage,” “CPU/NB Offset Voltage,” “Processor-NB Voltage,” and “APU-NB Over Voltage.”

If there is only one voltage option using the name “NB,” then it is probably used to configure the VDDNB voltage line.

If there are more voltage options showing up as “NB,” and the motherboard also has a “CPU/NB Voltage” option, these other options are for the chipset and not for the CPU. For a real example, consider a motherboard that has these three options: “CPU/NB Voltage,” “NB Voltage” and “NB 1.8 V Voltage.” The first option refers to the CPU VDDNB line (memory controller, HyperTransport interface, and L3 cache), while the other two refer to the motherboard chipset.

The default voltages vary depending on the CPU. One of the first things a serious overclocker should do before trying to change voltage options is to discover what the default values are for the CPU. This can be found in a document from AMD called “Power and Thermal Data Sheet,” which has a version for each CPU family.

AMD Processors Chipset Options

Chipset-related options include all voltages that are not the ones described on the previous page. They include:

Intel Processors

Intel processors use the following voltages (the names below are the official ones):

Now let’s take a look at the memory options.

Intel Processors Memory Options

While all CPUs from AMD have an embedded memory controller, this is not true with models from Intel, where only the newer models (Core i3, Core i5 and Core i7) have this feature. Therefore, voltages present on the memory bus can be produced either by the CPU or by the North Bridge chip from the chipset (MCH, Memory Controller Hub), depending on the platform you have. This is why we are posting memory-related voltages on a separate page.

The memory bus requires three different voltages:

Intel Processors Chipset Options

Chipset-related options include all voltages that are not the ones described in the previous page. They include:

Originally at http://www.hardwaresecrets.com/article/Understanding-All-Voltage-Configurations-from-the-Motherboard/995


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