8800GT PCI-E link only running at x1 speed

had same problem have a gigabyte 965p-ds3 rev 3.3 (same motherdoard just came with latter bios) worked fine with a nvidia 8500gt got a asus 8800gs scores were less than half what i was expecting used trial and error after a whole day found that by raising the voltage 0.1v on the PCI-E OVERVOLTAGE CONTROL in the bios in the mb intelligent tweaker section this fixed my problem i think the gigabyte motherboard may be supplying less voltage than needed by the 8800 series cards..... try 0.1v or 0.2v cant remember if it goes any higher but be carefull and watch the temps on the graphics card no problems on mine but have large case +6fans
scores in 3d mark 06 went from 4000 or so to over 11000 when overclocked hope this helps

have had mine running at +0.1v for 2 months now no trouble have had no increase in temp at all and i am running the 8800gs overclocked at 675 core 1700 shaders 1900 mem about a 20% overclock all at safe temps and stable but the choice is yours , but you seem to have overclocked your 6300 to 2.8 nice overclock i have my e4300 at 3ghz 9x334
try +0.1v see what happens this may not be your problem but it worked for me good luck.......................