Is a PCI express 16 bus or the latest AGP bus faster?

Answer 1

PCI x16 's bandwith far exceeds that of all other current expansion slots on home PC's. In other words make sure all your add-on cards are of this type if you motherboard can handle it. The Following table should give a good measurement of where we are at:
Common Buses and their Max Bandwidth PCI 132 MB/s AGP 8X 2,100 MB/s PCI Express 1x 250 [500]* MB/s PCI Express 2x 500 [1000]* MB/s PCI Express 4x 1000 [2000]* MB/s PCI Express 8x 2000 [4000]* MB/s PCI Express 16x 4000 [8000]* MB/s PCI Express 32x 8000 [16000]* MB/s IDE (ATA100) 100 MB/s IDE (ATA133) 133 MB/s SATA 150 MB/s Gigabit Ethernet 125 MB/s IEEE1394B [Firewire] 100 MB/s

* Note - Since PCI Express is a serial based technology, data can be sent over the bus in two directions at once. Normal PCI is Parallel, and as such all data goes in one direction around the loop. Each 1x lane in PCI Express can transmit in both directions at once. In the table the first number is the bandwidth in one direction and the second number is the combined bandwidth in both directions. Also please note that in PCI Express bandwidth is not shared the same way as in PCI, so there is less congestion on the bus.