PCI-E 2.0 Compatibility

Hi,

I wanted to buy a graphic card for my friend which supports the new PCI-E 2.0 architecture, specifically this one
http://www.newegg.com/Product/Prod [...] 6814130319

Trouble is that his motherboard is a crappy old Intel D946GZIS
http://www.intel.com/products/desk [...] erview.htm
which has a 'PCI EXPRESS X16' slot. But it does not specify whether its a 1.0a or 1.1 slot.

Bottom line: Will the motherboard be able to run this card?

I know these cards are power hungry. Will a 460W power supply with dual 12V rails of 18A each, suffice?

"Q6: Will PCIe 3.0 products be compatible with existing PCIe 1.x and PCIe 2.0 products?
A6: PCI-SIG is proud of its long heritage of developing compatible architectures, and its members have consistently produced compatible and interoperable products. In keeping with this tradition, PCIe 3.0 will be fully compatible with prior generations of this technology, from software to clocking architecture to mechanical interfaces. That is to say PCIe 1.x and 2.0 cards will seamlessly plug into PCIe 3.0-capable slots and operate at their highest performance levels. Similarly, all PCIe 3.0 cards will plug into PCIe 1.x- and PCIe 2.0-capable slots and operate at the highest performance levels supported by those configurations." Thay made the standard.http://www.pcisig.com/news_room/faqs/pcie3.0_faq