ECS Nforce4-A939 NVIDIA NFORCE4 Chipset driver(where)?

Should I use the one from ECS.com.tw or I should get it from nvidia.com ?

http://www.ecs.com.tw/ECSWebSite/Products/ProductsDetail.aspx?detailid=493&DetailName=Driver&MenuID=1&LanID=9

Or

http://www.nvidia.com/object/nforce_nf4_win2k_6.86.html

Can someone tell me what's SMBUS driver for? Do I need to install that?
the nVidia driver set will be the most up-to-date driver available. I've found there is a decent delay before the manufacturers have the same driver available.

Someone's probably going to chime in with a more "technical" answer, but yeah, go ahead and install the SMBus driver. I believe it's for your IDE and SATA drives.