Only update your BIOS if you specifically know that an upgrade will solve a problem. Read the BIOS version release notes to determine this.
You do stand a risk of trashing your Motherboard and the level of risk depends on a number of factors.
My Computer
Computer type
PC/Desktop
Computer Manufacturer/Model Number
Own build
OS
Windows 7x64 Home Premium SP1
CPU
Intel i7 2600k
Motherboard
ASUS P8Z68 Deluxe
Memory
G.Skill Ripjaws (DDR3-1600) 2x4GB
Graphics Card(s)
Nvidia GeForce GTS 450; Intel HD Graphics 3000(GT2+)
+1, I never update BIOS unless it solves a problem, or adds a new feature that I desire (usually doesn't). They mostly update for support of new CPU's it seems. A Guy
Yes and no. If your PC is currently working fine, and you don't plan on upgrading any hardware like your Processor, flashing your BIOS will not improve performance.
If you are having issues and a newer version BIOS has a fix for it, then yes it should improve things.
If you plan on upgrading your processor but your current BIOS doesn't support it, flashing to a BIOS that does will improve performance. The performance gain is from the new Processor though, not the new BIOS.
By itself a newer BIOS generally won't improve performance. In conjunction with new hardware though it may be worth taking the risk of flashing it. If you are having issues you may not have a choice if you want a stable system. Just keep in mind that flashing the BIOS is not the same thing as updating a driver. If you get it wrong you could brick your motherboard. If your motherboard has boot block or dual BIOS its not that big a risk. I've done it a dozen or so times without any problems. If you are going to do it, and have never done it before print the instructions out on paper before you start. I've done it from Windows, from the BIOS itself, and from bootable media. Doing it from the BIOS itself if it has the routine built in seems to me to be the safest method.
My Computer
Computer type
PC/Desktop
Computer Manufacturer/Model Number
Home Built
OS
Windows 10 Education 64 bit
CPU
AMD Phenom II X4 980 Black Edition Deneb 3.7GHz
Motherboard
Asus M4N68T-M V2 µATX Motherboard
Memory
8GB 4GBx2 Kingston PC10600 DDR3 1333 Memory
Graphics Card(s)
Zotac NVIDIA Geforce GT640 2 Gig DDR3 PCIe
Sound Card
VIA VT1708s High Definition Audio 8-channel Onboard