BIOS Setup

Functionality

ASUS P5N-D mainboard uses BIOS based on Phoenix-Award code. It looks pretty common for an ASUS BIOS and consists of several large sections: Main, Advanced, Power, Boot, Tools and Exit. Each section may include a few sub-sections. First we get to the Main section offering only a few major functions, such as setting system time and date, selecting the language:

Advanced section has much more sub-sections and features:

Let’s check out the JumperFree Configuration sub-section first. By setting AI Tuning to AI Overclock we can use the automatic overclocking system:

However, you can overclock your CPU by only 20% maximum, so we will change AI Tuning to Manual to get full access to the board’s overclocking friendly functions.

Despite the attractive name, the “System Clocks” page has only one parameter: NB PCIE Frequency. It allows changing the PCI Express bus frequency in the interval from 100MHz to 131MHz. So, we will not stay here for long and move on to the next page called Voltage Control.

Vcore Voltage parameter can be adjusted from 0.83125V to 1.6V with 0.00625V increment. Other voltages can be changed with 0.02V increment in the following intervals:

• DRAM Voltage: 1.85-3.11V;
• HT (HyperTransport) Voltage: 1.2-1.96V;
• NB Chipset Voltage: 1.2-1.76V;
• SB Chipset Voltage: 1.5-1.86V.

These are pretty wide ranges, the increment is quite small and the parameters can be changed very easily. For example, just select one of the parameters and you will immediately see the supported range in the right-hand side of the screen.

For the CPU Vcore you will see not only the supported voltage interval but also a special warning. It will remind you of a well-known ASUS mainboard issue: any changes to the processor Vcore when it is not longer set to Auto mode will disable all power-saving technologies.

It is great that they admit to having this issue and honestly warn the user about it, but I wish they had resolved it instead.

FSB & Memory Config page from the JumperFree Configuration section offers us to enjoy Nvidia’s chipset’s rich functionality in setting the FSB to Memory ratio. It is way more flexible here than what Intel chipsets have to offer.

We can select Linked mode when the memory frequency is tied up to the FSB speed with a few dividers. This operational mode is absolutely identical to the way the memory frequency is set in Intel chipsets.

However, there is also Unlinked mode that offers almost unlimited choices for FSB to Memory frequency. Just set the desired FSB speed in the interval from 533MHz to 3000MHz QDR (they use 4x FSB frequency, i.e. 133MHz to 750MHz interval in conventional measuring units) and the desired memory frequency in the interval from 400MHz to 2600MHz (!). You don’t have to know or remember anything about dividers: the mainboard will find the correct one on its own so that the resulting memory frequency could be as close to the desired one as possible.

In any way Actual FSB (QDR) and Actual MEM (DDR) parameters will report the expected actual FSB and memory frequencies.