Some games can use a dedicated card for PhysX simulation. Other
than that, I can't come up with anything that the second card
could be used for (in terms of enhancing performance). The
difference between x1, x2, x4, x8 and x16 PCIe is the maximum
throughput of the bus (how much data can pass between the card
and the rest of the system in a given time). Directron lists the
following speeds: PCI Express 1x 250 * MB/s PCI Express 2x 500 *
MB/s PCI Express 4x 1000 * MB/s PCI Express 8x 2000 * MB/s PCI
Express 16x 4000 * MB/s PCI Express 32x 8000 * MB/s * Note 1 -
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 sam