"Accelerated Graphics Port". An interface specification from Intel that enables 3-D graphics to display quickly on personal computers. AGP is based on PCI, but is designed especially for the high throughput requirements of 3-D graphics. Rather than using the PCI bus for graphics data, AGP introduces a dedicated point-to-point channel so that the graphics controller can directly access main memory.
Most likely, infact Iam very certain that the Geforce 6 6600, WILL fit in-to a AGP Slot.