disabling devices in motherboard BIOS: does it save on power?
I've always wondered if disabling devices via BIOS saves on power?
some full feature motherboard have all sorts of devices I never used. Firewire, built-in WiFi, audio (for my servers) and etc.
Thanks! :)
ps. I did a net search but nothing useful came up.
Yes, it does save power. If a device on your motherboard is enabled, it will draw power, even if it is not being used. Depending on the device and your power management settings, your OS may turn them off, or at least into a low power state.
As stated before, yes, you are using more power and memory. However, the amount is hugely insignificant compared to the use of the CPU, graphics cards, and even the fans.
Generally, if you arent using an onboard device, disable it in BIOS. This will prevent it from getting power at all. In addition to that, the OS doesnt have to load drivers for those devices, which uses a small amount of memory. But more importantly, in my opinion, you wont accidentally confuse one device for another, as it wont be visible to the OS.
Yes, you can leave them on with no detriment, but personally I say if its not being used, dont leave it enabled. You can always turn it on later.
It depends on the peripheral in question and the driver.
It's rare for the device to actually be powered off completely. More commonly, the device is placed into a low power sleep state and the BIOS does not report information about it to the OS.
The OS driver will most likely also place the device in a lower power state. So the question becomes, is the BIOS setting lower power than the driver setting.
In some cases they may be the same, e.g. for disabled GPUs, sound and serial ports. In some cases the OS may keep the device powered up to some extent, e.g. a network port that can detect when a cable is plugged in. It may also depend on if you disable the device or merely leave it idle in the OS.
It's likely the disabling the device in the BIOS is a fairly safe bet for low power, but it's also possible that the driver might contain newer, more up to date code that does a better job.
This is largely implementation-dependent. It's certainly possible to implement advanced power saving features in BIOS which would be unavailable on the OS level. It's also possible that the device disabled in BIOS will simply not be reported to the OS and remain in "uninitialised" state, similar to devices which you disable on the OS level.
Sometimes, a single IC implements several functions which are seen as separate "devices" by the OS (e.g. WiFi+Bluetooth adapters). For such ICs, the actual power consumption may vary depending on which combinations of devices are disabled, while disabling a single device may have no effect on power consumption.