You're motherboard appears to have a PCI-E selection style card to choose between splitting the bus between 8x and 16x. If am correct...switching the card around should re-route the remaining 8x pipes towards the single slot, giving you 16x total. Of course the performance difference is non-existent since a Geforce 6600 just doesn't use up that much bandwith, but still nice for gloating with 16x over 8x .