MSI 8800 GT 512 MB compatible with Windows XP

Question

 Can somebody give me an assist on this. I am planning on buying an MSI GeForce 8800GT 512 MB
Video card. Newegg has these in stock but the spec only indicated Directx 10 support not
DirectX 9 or 9c support. Is the card downward compatible? Anyone running this card under
windows XP.
Like everyone else I need this upgrade to run Crysis demo. With my existing card and
everything overclocked I can run crysis demo at low res with low settings with strange
artifacts now and then.
Abit Fatal1ty AN9 32X
AMD Athlon 64 X@ Dual Core 5000+
3Gig G.Skill DDR2
EVGA GeForce7300Gt 512 MB

Answer 1

Don't worry, found this on anandtech.com:
The transition to PCIe 2.0 won't be anything like the move from AGP to PCIe. The cards and motherboards are backwards and forwards compatible. PCIe 1.0 and 1.1 compliant cards can be plugged into a PCIe 2.0 motherboard, and PCIe 2.0 cards can be plugged into older motherboards. This leaves us with zero impact on the consumer due to PCIe 2.0, in more ways than one.  
URL: http://www.anandtech.com/video/showdoc.aspx?i=3140&p=4
and this on tomshardware.com:
Finally, the GeForce 8800GT introduces PCI Express 2.0 support, which will double the bandwidth (moving up to a bi-directional 8 GB/s) with an X38 motherboard. This won't change anything from a gaming point of view, but could be more interesting for workstations, professional software or applications using Nvidia's GPGPU CUDA. It remains, of course, fully compatible with PCI Express 1.0.
URL: http://www.tomshardware.com/2007/10/29/geforce_8800_gt/page2.html