Is it neccessary to have a PCIe x16 2.0 slot for installing an Ati Radeon HD 3850 ?

Question

Could I install a PCIe x16 2.0 graphic card like Ati Radeon HD 3850 on a Mobo with support PCIe x16 1.0 like Gigabyte
GA-m55s-s3 ?
If Yes, does it take lower performance ?

Answer 1

Just like the 8800GT it is backward compatible with PCIe 1.1 in older motherboards, according to this article (middle part of page).
http://techreport.com/articles.x/13603/2

I believe there would be no reduction in performance on your board. It is the dual or multicard set ups that would really benefit most from the wide bandwidth of PCIe 2.0.