BIOS tips and tweaks for speed and extra functionality

Unlock the secrets of your PC's BIOS

Power is the section where your motherboard shows off its green credentials with a range of power-saving and sleep-related settings.

Suspend mode

Also known as ACPI Suspend Type, this setting decides how Sleep mode will work on your PC. Set this to 'S3' to turn off almost every device, meaning that the system will use very little power (for example, only 8W on our test PC).

If you have problems getting devices to work after your PC wakes up – and driver updates don't help – then you could use 'S1' Suspend Mode (or 'S1 Only') instead. This keeps more devices awake and so improves compatibility, but at the cost of much greater electricity consumption – 195W on our test system.

Repost video on S3 resume

Re-initialises the video BIOS after waking up from an S3 sleep. Disable this and your PC might wake more quickly, but you also might find that there's nothing on the display – a real problem if there are important documents you need to save. If you disable the setting, test it first to make sure that your video card resumes properly.

Power on by RTC alarm

Uses the real-time clock to automatically fire up the PC at the time of your choice.

Power on by PS/2 keyboard

If you've got an old-style keyboard that uses a PS/2 connection (not USB), this setting lets you turn on your PC just by pressing a key.

Power on by PCI/PCIe devices

Also known as 'Wake-On-LAN', this is most useful for waking up your PC when it detects network activity. Set everything up properly and you can even start your PC over the internet. Combine this functionality with a remote access tool like LogMeIn in order to access your files when you're away from home.

Also known as PC Health Status (and sometimes found as a submenu under the Main, Power or Advanced menus), this is where you'll find details on component temperatures, voltages and fan speeds.

Overclockers should check this section to ensure their tinkering isn't pushing their system too far. If you're experiencing odd PC problems that may be caused by overheating, you'll want to check here too.

Voltage monitor

Displays the voltages of your PC, CPU, memory, system bus and more.

Temperature monitor

Keep an eye on your CPU, MB (motherboard), NB (Northbridge) and SB (Southbridge) temperatures here. Every system is different, but our i7 920 system varied from around 30 to 50°C depending on setup and load. There are normally options to prevent overheating, too.

For example, our test PC had an 'overheat protection' setting that would automatically turn the PC off if the Northbridge or Southbridge exceeded 90°C. If your PC sometimes turns off unexpectedly then this could be the cause.

Fan speed monitor

This section tracks the current speed of your PC's fans.

Fan speed control

Most BIOSes have their own ways of varying fan speed according to circumstances. On our test system, for instance, we can set a particular fan to 'User mode' and then define the temperature when it will hit full speed (60°C by default).

Asus boards also provide something called Q-Fan, which lets you choose your fan speeds from one of three profiles: 'Silent' optimises your fans for minimal noise, 'Turbo' is noisy but keeps your system as cool as possible, while 'Standard' is somewhere in between.