I've updated the bios on a lot of computers and never ever had a problem, so I'd say go ahead and do it.
I bought my Daughter a lovely 17" HP Pavilion laptop a few years ago and she found that it ran pretty hot, so much so that it occasionally shut itself down. For various reasons I never actually got to look into it until it was recycled in my direction last year. It was so hot that I'm surprised that the case hadn't melted. Tried a bios update as a last resort and it was like a new machine - cool until really pushed. Lord knows what they'd done wrong first time round but they fixed it. Maybe you'll be equally lucky?