Hi,
What is it about bios update? is it recommanded? ???
Thanks.

Generally speaking BIOS upgrades are recommended only by manufacturers if you're experiencing issues, but then the same recommendation is applied to drivers. Really, it's to prevent people who don't really know what they're doing, buggering their motherboard.

Motherboard BIOS usually fix bugs and add identifier strings for new CPUs. New BIOSs only rarely improve performance, and that's only if they make accessable a motherboard feature, or improve configuration options.

I personally recommend BIOS upgrades to non-experts only if you're experiencing a problem with a new hardware device. There is a risk of a flash doing wrong, which can render the system non-bootable.