Do BIOS Upgrades Really Matter?

inkfox asks: "It seems that whenever one buys a motherboard, there's already a BIOS upgrade available by the time you get your hands on it, usually dealing with some degenerate hardware behavior. Given that Linux and Windows 2000/XP replace all BIOS routines once loaded, do these upgrades really matter? If a system is successfully booting, is a BIOS upgrade more a risk than it is preventive maintenance?" This may be true, but what if you are running an OS that depends on the BIOS? If the BIOS is replaced by a specific OS, then BIOS upgrades can't really hurt anything, can they?

Comments

More than just code

[toastyman]

Unfortunately, there's alot of stuff in your BIOS that isn't executable code. If your system has a PCI or Cardbus slot, you've got a "PCI Routing Table" which tells the OS how each slot has its interrupts mapped, and the such.

If you're using a SMP system, there's a "MP Table" which tells the OS how to configure the APICs, interrupt triggering, etc.

There also is a little bit of code that many OS's use for power management (suspend, hybernate, sleep, etc), that's a pain in the ass to access from protected mode.

Also, almost everything on the motherboard is configured during the POST and bootup. All sorts of timing values, drive strengths, etc. The OS generally won't touch any of this. New BIOS's sometimes change these default values to what the manufacturer has discovered to be better settings.

If you're having PROBLEMS with something, by all means upgrade, even if you don't think your OS is actually calling any code in the BIOS. But if it works, I generally recommend people to avoid playing with it. I've removed ROMs from a few friends' motherboards, just to correct damage they did from flashing the wrong BIOS on them. (Surface mount soldering tools and a eeprom/flash programmer are very handy at times)

Not true

[photon317]

Even under Linux, or any other OS that avoids the BIOS when at all possible, your BIOS still plays very important roles. I have in the past solved numerous problems on linux boxes with bios upgrades, mostly issues like memory timing, irq routing, PnP support, PCI latency issues...

Also, don't forget that modern processors are no longer set in stone.... all the newer processors (from the PII-era onwards I believe) from Intel and AMD have some form of updateable microcode on the processor, so that little quirks and bugs can be worked around when they're discovered.

Your processor uses it's hardware default microcode every time it is rebooted, and then the BIOS updates it with the latest-greatest shortly after each bootup. Keeping your BIOS up to date is therefore the only path to keeping your processor up to date as well (newer BIOS updates contain the newest microcde from the chip vendor).